December 2013 - discuss - mailman3.cels.anl.gov

Re: [mpich-discuss] Fwd: Can't receive messages
by Reuti 30 Dec '13

30 Dec '13

Hi, Am 30.12.2013 um 10:58 schrieb Matthias Neuer: > Unfortunately, this does not solve the problem. > > Maybe I should have written that the program hangs after the output in my last post. It waits until MPI_Recv returns which does not happen. > > By the way I can login from one machine to the other using ssh, no problem. For me it's working even without `fflush`. Do you see anything in the "messages" file on the machine where rank 0 is running? Just for curiosity: does adding an MPI_Barrier before the MPI_Finalize change anything for you? -- Reuti > Thanks > > On 12/30/2013 06:39 AM, Rajeev Thakur wrote: >> Try adding an fflush(stdout) after the printf after the recv. >> >> On Dec 29, 2013, at 12:50 PM, Matthias Neuer <mneuer(a)web.de> wrote: >> >>> >>> >>> >>> -------- Original Message -------- >>> Subject: Can't receive messages >>> Date: Sun, 29 Dec 2013 19:00:05 +0100 >>> From: Matthias Neuer <mneuer(a)web.de> >>> To: discuss(a)mpich.org >>> >>> Hi. >>> >>> I installed MPICH on 2 machines (called notebook and matze-debian) using >>> the same sourcecode. The output of mpichversion is both times: >>> >>> MPICH Version: 3.0.4 >>> MPICH Release date: Wed Apr 24 10:08:10 CDT 2013 >>> MPICH Device: ch3:nemesis >>> MPICH configure: --disable-f77 --disable-fc >>> --prefix=/home/matze/mpich-install >>> MPICH CC: cc -O2 >>> MPICH CXX: c++ -O2 >>> MPICH F77: no >>> MPICH FC: no >>> >>> I wrote a small test program which I send as an attachment. >>> On execution on the machine matze-debian I get the following: >>> >>> Process 0 is on matze-debian >>> Process 2 is on matze-debian >>> Process 1 is on notebook >>> received: Hello, from number 2 on matze-debian >>> Process 2 has sent the message >>> Process 1 has sent the message >>> >>> I don't receive the message from process number 1, but the output >>> suggests that the message was succesfully sent. Actually I checked the >>> network traffic using wireshark and matze-debian received a package in >>> which I found the sent message. So somehow the program does not >>> recognize the arrival of the message. >>> >>> When I run the program on a single machine it works. >>> >>> I don't know if this is a programming error or a configuration error. >>> >>> Thanks for your help >>> >>> >>> >>> <ex1.c>_______________________________________________ >>> discuss mailing list discuss(a)mpich.org >>> To manage subscription options or unsubscribe: >>> https://lists.mpich.org/mailman/listinfo/discuss >> >> _______________________________________________ >> discuss mailing list discuss(a)mpich.org >> To manage subscription options or unsubscribe: >> https://lists.mpich.org/mailman/listinfo/discuss >> > > _______________________________________________ > discuss mailing list discuss(a)mpich.org > To manage subscription options or unsubscribe: > https://lists.mpich.org/mailman/listinfo/discuss

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Re: [mpich-discuss] Fwd: Can't receive messages
by Matthias Neuer 30 Dec '13

30 Dec '13

Hi. Unfortunately, this does not solve the problem. Maybe I should have written that the program hangs after the output in my last post. It waits until MPI_Recv returns which does not happen. By the way I can login from one machine to the other using ssh, no problem. Thanks On 12/30/2013 06:39 AM, Rajeev Thakur wrote: > Try adding an fflush(stdout) after the printf after the recv. > > On Dec 29, 2013, at 12:50 PM, Matthias Neuer <mneuer(a)web.de> wrote: > >> >> >> >> -------- Original Message -------- >> Subject: Can't receive messages >> Date: Sun, 29 Dec 2013 19:00:05 +0100 >> From: Matthias Neuer <mneuer(a)web.de> >> To: discuss(a)mpich.org >> >> Hi. >> >> I installed MPICH on 2 machines (called notebook and matze-debian) using >> the same sourcecode. The output of mpichversion is both times: >> >> MPICH Version: 3.0.4 >> MPICH Release date: Wed Apr 24 10:08:10 CDT 2013 >> MPICH Device: ch3:nemesis >> MPICH configure: --disable-f77 --disable-fc >> --prefix=/home/matze/mpich-install >> MPICH CC: cc -O2 >> MPICH CXX: c++ -O2 >> MPICH F77: no >> MPICH FC: no >> >> I wrote a small test program which I send as an attachment. >> On execution on the machine matze-debian I get the following: >> >> Process 0 is on matze-debian >> Process 2 is on matze-debian >> Process 1 is on notebook >> received: Hello, from number 2 on matze-debian >> Process 2 has sent the message >> Process 1 has sent the message >> >> I don't receive the message from process number 1, but the output >> suggests that the message was succesfully sent. Actually I checked the >> network traffic using wireshark and matze-debian received a package in >> which I found the sent message. So somehow the program does not >> recognize the arrival of the message. >> >> When I run the program on a single machine it works. >> >> I don't know if this is a programming error or a configuration error. >> >> Thanks for your help >> >> >> >> <ex1.c>_______________________________________________ >> discuss mailing list discuss(a)mpich.org >> To manage subscription options or unsubscribe: >> https://lists.mpich.org/mailman/listinfo/discuss > > _______________________________________________ > discuss mailing list discuss(a)mpich.org > To manage subscription options or unsubscribe: > https://lists.mpich.org/mailman/listinfo/discuss >

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Re: [mpich-discuss] Fwd: Can't receive messages
by Rajeev Thakur 29 Dec '13

29 Dec '13

Try adding an fflush(stdout) after the printf after the recv. On Dec 29, 2013, at 12:50 PM, Matthias Neuer <mneuer(a)web.de> wrote: > > > > -------- Original Message -------- > Subject: Can't receive messages > Date: Sun, 29 Dec 2013 19:00:05 +0100 > From: Matthias Neuer <mneuer(a)web.de> > To: discuss(a)mpich.org > > Hi. > > I installed MPICH on 2 machines (called notebook and matze-debian) using > the same sourcecode. The output of mpichversion is both times: > > MPICH Version: 3.0.4 > MPICH Release date: Wed Apr 24 10:08:10 CDT 2013 > MPICH Device: ch3:nemesis > MPICH configure: --disable-f77 --disable-fc > --prefix=/home/matze/mpich-install > MPICH CC: cc -O2 > MPICH CXX: c++ -O2 > MPICH F77: no > MPICH FC: no > > I wrote a small test program which I send as an attachment. > On execution on the machine matze-debian I get the following: > > Process 0 is on matze-debian > Process 2 is on matze-debian > Process 1 is on notebook > received: Hello, from number 2 on matze-debian > Process 2 has sent the message > Process 1 has sent the message > > I don't receive the message from process number 1, but the output > suggests that the message was succesfully sent. Actually I checked the > network traffic using wireshark and matze-debian received a package in > which I found the sent message. So somehow the program does not > recognize the arrival of the message. > > When I run the program on a single machine it works. > > I don't know if this is a programming error or a configuration error. > > Thanks for your help > > > > <ex1.c>_______________________________________________ > discuss mailing list discuss(a)mpich.org > To manage subscription options or unsubscribe: > https://lists.mpich.org/mailman/listinfo/discuss

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Fwd: Can't receive messages
by Matthias Neuer 29 Dec '13

29 Dec '13

-------- Original Message -------- Subject: Can't receive messages Date: Sun, 29 Dec 2013 19:00:05 +0100 From: Matthias Neuer <mneuer(a)web.de> To: discuss(a)mpich.org Hi. I installed MPICH on 2 machines (called notebook and matze-debian) using the same sourcecode. The output of mpichversion is both times: MPICH Version: 3.0.4 MPICH Release date: Wed Apr 24 10:08:10 CDT 2013 MPICH Device: ch3:nemesis MPICH configure: --disable-f77 --disable-fc --prefix=/home/matze/mpich-install MPICH CC: cc -O2 MPICH CXX: c++ -O2 MPICH F77: no MPICH FC: no I wrote a small test program which I send as an attachment. On execution on the machine matze-debian I get the following: Process 0 is on matze-debian Process 2 is on matze-debian Process 1 is on notebook received: Hello, from number 2 on matze-debian Process 2 has sent the message Process 1 has sent the message I don't receive the message from process number 1, but the output suggests that the message was succesfully sent. Actually I checked the network traffic using wireshark and matze-debian received a package in which I found the sent message. So somehow the program does not recognize the arrival of the message. When I run the program on a single machine it works. I don't know if this is a programming error or a configuration error. Thanks for your help

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Re: [mpich-discuss] MPI memory allocation.
by Anatoly G 28 Dec '13

28 Dec '13

In addition to previous mail. I got some report improvements. Now program fails faster. Program fails with report in shell: Assertion failed in file src/mpid/ch3/channels/nemesis/src/ch3_progress.c at line 640: pkt->type >= 0 && pkt->type < MPIDI_NEM_PKT_END internal ABORT - process 0 More errors in out*.log files. In new version *no fail* with 10 processes, but fails with 20. execute command: mpiexec.hydra -genvall -f MpiConfigMachines1.txt -launcher=rsh -n 20 /home/anatol-g/Grape/release_under_constr_MPI_tests_quantum/bin/linux64/rhe6/g++4.4.6/debug/mpi_rcv_any_multithread 100000 1000000 -1 -1 1 out Please help, Regards, Anatoly. On Sun, Dec 29, 2013 at 6:55 AM, Anatoly G <anatolyrishon(a)gmail.com> wrote: > Good morning. > I hope that I understand you. > I changed my test program to print network rate (not real network rate, > but pure data rate after finish each send or receive). > My application fails before finishing execution. I attach my program, and > the results. No core file created. I use unlimit option, then fails of my > programs cause core file creation. > > execute command: > mpiexec.hydra -genvall -f MpiConfigMachines1.txt -launcher=rsh -n 10 > /home/anatol-g/Grape/release_under_constr_MPI_tests_quantum/bin/linux64/rhe6/g++4.4.6/debug/mpi_rcv_any_multithread > 100000 1000000 -1 -1 1 out > > Can you please advice. I completely don't understand why program fails. > If anything is not clear, please reply and I will try to complete my > explanation. > > Regards, > Anatoly. > > > On Wed, Dec 25, 2013 at 6:38 PM, Pavan Balaji <balaji(a)mcs.anl.gov> wrote: > >> >> I have no idea what I need to do with your benchmark since you are >> relying on an external tool to give performance debugging information. >> FWIW, there will be a memory increase in MPI_Init. That’s expected and >> not bad. If you post a bunch of isends, some of them get buffered locally, >> while others have to wait for the necessary flow-control. So it might look >> like your network performance has dropped. Again, this is expected. I >> don’t know if these are what you are seeing or if it’s a different problem. >> But I can’t tell from your benchmark. >> >> It might be easier for us if your application does internal profiling of >> memory and communication and printed it out directly. That way, I know >> what you are measuring more accurately. >> >> — Pavan >> >> On Dec 23, 2013, at 7:19 PM, Anatoly G <anatolyrishon(a)gmail.com> wrote: >> >> > Hi. >> > Do you need more info to reproduce problem? >> > >> > Anatoly. >> > >> > >> > On Sun, Dec 22, 2013 at 7:54 AM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > Good morning Pavan. >> > Do you see process memory raise & network throughput low behavior? >> > >> > Anatoly. >> > >> > >> > On Thu, Dec 19, 2013 at 7:09 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > No. You can see memory increase using monitor like "qps", or any other. >> > The stack trace that I send I get when I stop my real program (not >> simulation) with TotalView debugger. >> > if you monitor network traffic, you will see network speed which >> becomes low until it reaches almost 0. >> > >> > Anatoly. >> > >> > >> > On Thu, Dec 19, 2013 at 5:16 PM, Pavan Balaji <balaji(a)mcs.anl.gov> >> wrote: >> > >> > Are you printing it out? >> > >> > — Pavan >> > >> > On Dec 19, 2013, at 10:51 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > >> > > Can you please remove comment from section >> > > /* >> > > // swap tag & enter blocked recv >> > > MPI_Status stat; >> > > tags[slaveIdx] = (tags[slaveIdx] == TAG1) ? TAG2 : TAG1; >> > > MPI_Recv(RcvBufs[slaveIdx], BUF_SZ, MPI::CHAR, slaveRank, >> tags[slaveIdx], MPI_COMM_WORLD, &stat); >> > > >> > > ++SlavesRcvIters[slaveIdx]; >> > > */ >> > > >> > > And then run it. >> > > Do you see memory allocation increase? >> > > >> > > Regards, >> > > Anatoly. >> > > >> > > >> > > On Thu, Dec 19, 2013 at 4:29 PM, Pavan Balaji <balaji(a)mcs.anl.gov> >> wrote: >> > > >> > > I’m not sure what I should look for. I ran the program and it >> completed fine. >> > > >> > > — Pavan >> > > >> > > On Dec 19, 2013, at 7:16 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > >> > > > Good afternoon. >> > > > My program enters a lot to attached stack functions. >> > > > Can you please explain if it's ok? >> > > > Did you success to execute simulation from previous mail. >> > > > Did you see the memory raise when MPI_Recv not in comments? >> > > > >> > > > Regards, >> > > > Anatoly. >> > > > >> > > > >> > > > On Thu, Dec 12, 2013 at 9:36 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > Hi. >> > > > Finally, I got an additional info. >> > > > I build short simulation of my real application. >> > > > >> > > > The short description of real scenario. >> > > > I have Master + N slaves. Each slave sends to Master 2 types of >> messages: >> > > > • constant length message with predefined fields (one of it's >> fields is length of second message). >> > > > • second message - length of this message each time is >> different and passed in first message. >> > > > Master should use MPI_Irecv commands, in order to be tolerant to >> slaves failure (blocked MPI_Recv is blocking Master in the failure case). >> > > > Master executes MPI_Irecv to each slave with buffer size equal to >> the constant size of first message type. After receiving first type of >> message, Master allocates expected buffer for second message and performs >> receive too. This happens in endless loop for each slaves. I use >> MPI_Waitany to monitor all receives. >> > > > In order to separate messages Master & slaves use different tags >> (as ids) for first & second messages. >> > > > >> > > > Simulation description: >> > > > All passed buffers (first & second) have the same size. >> > > > Slave (SndSyncSlave) sends messages and swaps 2 tags between them >> (like 2 types of messages, but second one has constant size too). >> > > > Master routine (Rcv_WaitAny function) executes MPI_Irecv for first >> message, and after receive executes MPI_Irecv for the second one. >> > > > >> > > > In this scenario: 5 processes works fine, but if I execute 20 >> processes and remove comment from line "usleep(200000)" I see 800 Mbit/s >> on network at the test beginning, but after 1-2 second network speed become >> 200-300Kbit/s and not increased back any more. >> > > > >> > > > If I add MPI_Recv block in Master (remove comment from "MPI_Recv" >> and line around) I see that Master starts increase memory as my real >> application, but again on 5 processes this not happens. This is scenario >> used in my real application. >> > > > >> > > > Command line: mpiexec.hydra -genvall -f MpiConfigMachines.txt >> -launcher=ssh -n 20 mpi_rcv_any_multithread 100000 1000000 out >> > > > >> > > > where >> > > > 100000 - number of sends from each slave >> > > > 1000000 - scale to separate input from each scale (used for debug >> only) >> > > > out - prefix of output file. Each process produce out_"rank".txt >> file. >> > > > >> > > > MpiConfigMachines.txt - configuration file for my computers, 2 >> computers back to back 1 Gbit/s network. >> > > > >> > > > >> > > > Can you please test this case, and give me yours suggestions. >> > > > >> > > > Thank you, >> > > > Anatoly. >> > > > >> > > > >> > > > >> > > > On Mon, Dec 9, 2013 at 9:55 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > Yes, I understand that. I"ll try to make my stand alone test closer >> to real application. Thank you. >> > > > >> > > > >> > > > On Mon, Dec 9, 2013 at 9:31 PM, Pavan Balaji <balaji(a)mcs.anl.gov> >> wrote: >> > > > >> > > > It sounds like MPICH is working correctly. Without a test case, >> it’s unfortunately quite hard for us to even know what to look for. It’s >> also possible that there’s a bug in your code which might be causing some >> bad behavior. >> > > > >> > > > — Pavan >> > > > >> > > > On Dec 9, 2013, at 1:27 PM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > >> > > > > Yes, I"m actually need Fault tolerance, and it was the main >> reason for choosing MPICH2. I use fault tolerance for unpredictable bugs in >> the future. My system should survive partially. But in the regular case I >> just need full performance. I"m suspect that I don't use MPI correctly, but >> on slow rate everything works fine. The fail caused by increasing rate of >> MPI_Isend or increasing data buffer size. I didn't find yet any strong >> dependence, only main stream. >> > > > > >> > > > > Unfortunately I have a complex system which has a number of >> threads in each process. Part of the threads use different communicators. >> > > > > >> > > > > I try to simulate the same MPI behavior in simple stand alone >> test, but stand alone test works fine. It shows a full network performance, >> when I slow down master (on stand alone test), all slaves are stopped too >> and are waiting for master to continue. Can I open any MPICH log to send >> you the results? >> > > > > >> > > > > >> > > > > On Mon, Dec 9, 2013 at 8:10 PM, Pavan Balaji <balaji(a)mcs.anl.gov> >> wrote: >> > > > > >> > > > > Do you actually need Fault Tolerance (one of your previous emails >> seemed to indicate that)? >> > > > > >> > > > > It sounds like there a bug in either your application or in the >> MPICH stack and you are trying to trace that down, and don’t really care >> about fault tolerance. Is that a correct assessment? >> > > > > >> > > > > Do you have a simplified program that reproduces this error, that >> we can try? >> > > > > >> > > > > — Pavan >> > > > > >> > > > > On Dec 9, 2013, at 11:44 AM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > > >> > > > > > No. Hardware is Ok. Master process allocates memory (check >> with MemoryScape doesn't show any sufficient memory allocation in my code). >> Then network traffic become low, and then Master process crashes w/o saving >> core file. I have unlimited size of core files. The same fail (w/o core) I >> see when I call MPI_Abort, but I don't call it. >> > > > > > >> > > > > > >> > > > > > On Mon, Dec 9, 2013 at 7:28 PM, Wesley Bland < >> wbland(a)mcs.anl.gov> wrote: >> > > > > > Are you actually seeing hardware failure or is your code just >> crashing? It's odd that one specific process would fail so often in the >> same way if it were a hardware problem. >> > > > > > >> > > > > > Thanks, >> > > > > > Wesley >> > > > > > >> > > > > > On Dec 9, 2013, at 11:15 AM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > > > >> > > > > >> One more interesting fact. Each time I have a failure, the >> fails only master process, but slaves are still exists together with >> mpiexec.hydra. I thought that slaves should fail too, but slaves are live. >> > > > > >> >> > > > > >> >> > > > > >> On Mon, Dec 9, 2013 at 10:30 AM, Anatoly G < >> anatolyrishon(a)gmail.com> wrote: >> > > > > >> I configure MPICH-3.1rc2 build w/o "so" files. But instead of >> MPICH2 & MPICH-3.0.4 I get so files. What should I change in configure line >> to link MPI with my application statically. >> > > > > >> >> > > > > >> >> > > > > >> >> > > > > >> On Mon, Dec 9, 2013 at 9:47 AM, Pavan Balaji < >> balaji(a)mcs.anl.gov> wrote: >> > > > > >> >> > > > > >> Can you try mpich-3.1rc2? There were several fixes for this >> in this version and it’ll be good to try that out before we go digging too >> far into this. >> > > > > >> >> > > > > >> — Pavan >> > > > > >> >> > > > > >> On Dec 9, 2013, at 1:46 AM, Anatoly G <anatolyrishon(a)gmail.com> >> wrote: >> > > > > >> >> > > > > >> > With MPICH - 3.0.4 the situation repeated. It looks like MPI >> allocates memory for messages. >> > > > > >> > Can you please advice about scenario when MPI or may be TCP >> under MPI allocates memory due to high transfer rate? >> > > > > >> > >> > > > > >> > >> > > > > >> > On Mon, Dec 9, 2013 at 9:32 AM, Anatoly G < >> anatolyrishon(a)gmail.com> wrote: >> > > > > >> > Thank you very much. >> > > > > >> > Issend - is not so good, It can't support me Fault >> tolerance. If slave process fails, the master stall. >> > > > > >> > I tried mpich-3.0.4 with hydra-3.0.4 but my program which >> uses MPI Fault tolerance doesn't recognize failure of slave process, but >> recognizes failure with MPICH2. May be you can suggest solution? >> > > > > >> > I tried to use hydra from MPICH2 but link my program with >> MPICH3. This combination recognizes failures, but I"m not sure that such >> combination is stable enough. >> > > > > >> > Can you please advice? >> > > > > >> > Anatoly. >> > > > > >> > >> > > > > >> > >> > > > > >> > >> > > > > >> > On Sat, Dec 7, 2013 at 5:20 PM, Pavan Balaji < >> balaji(a)mcs.anl.gov> wrote: >> > > > > >> > >> > > > > >> > As much as I hate saying this — some people find it easier >> to think of it as “MPICH3”. >> > > > > >> > >> > > > > >> > — Pavan >> > > > > >> > >> > > > > >> > On Dec 7, 2013, at 7:37 AM, Wesley Bland <wbland(a)mcs.anl.gov> >> wrote: >> > > > > >> > >> > > > > >> > > MPICH is just the new version of MPICH2. We renamed it >> when we went past version 3.0. >> > > > > >> > > >> > > > > >> > > On Dec 7, 2013, at 3:55 AM, Anatoly G < >> anatolyrishon(a)gmail.com> wrote: >> > > > > >> > > >> > > > > >> > >> Ok. I"ll try both Issend, and next step to upgrade MPICH >> to 3.0.4. >> > > > > >> > >> I thought before that MPICH & MPICH2 are two different >> branches, when MPICH2 partially supports Fault tolerance, but MPICH not. >> Now I understand, that I was wrong and MPICH2 is just main version of MPICH. >> > > > > >> > >> >> > > > > >> > >> Thank you very much, >> > > > > >> > >> Anatoly. >> > > > > >> > >> >> > > > > >> > >> >> > > > > >> > >> >> > > > > >> > >> On Thu, Dec 5, 2013 at 11:01 PM, Rajeev Thakur < >> thakur(a)mcs.anl.gov> wrote: >> > > > > >> > >> The master is receiving too many incoming messages than >> it can match quickly enough with Irecvs. Try using MPI_Issend instead of >> MPI_Isend. >> > > > > >> > >> >> > > > > >> > >> Rajeev >> > > > > >> > >> >> > > > > >> > >> On Dec 5, 2013, at 2:58 AM, Anatoly G < >> anatolyrishon(a)gmail.com> wrote: >> > > > > >> > >> >> > > > > >> > >> > Hello. >> > > > > >> > >> > I"m using MPICH2 1.5. >> > > > > >> > >> > My system contains master and 16 slaves. >> > > > > >> > >> > System uses number of communicators. >> > > > > >> > >> > The single communicator used for below scenario: >> > > > > >> > >> > Each slave sends non-stop 2Kbyte data buffer using >> MPI_Isend and waits using MPI_Wait. >> > > > > >> > >> > Master starts with MPI_Irecv to each slave >> > > > > >> > >> > Then in endless loop: >> > > > > >> > >> > MPI_Waitany and MPI_Irecv on rank returned by >> MPI_Waitany. >> > > > > >> > >> > >> > > > > >> > >> > Another communicator used for broadcast communication >> (commands between master + slaves), >> > > > > >> > >> > but it's not used in parallel with previous >> communicator, >> > > > > >> > >> > only before or after data transfer. >> > > > > >> > >> > >> > > > > >> > >> > The system executed on two computers linked by 1Gbit/s >> Ethernet. >> > > > > >> > >> > Master executed on first computer, all slaves on other >> one. >> > > > > >> > >> > Network traffic is ~800Mbit/s. >> > > > > >> > >> > >> > > > > >> > >> > After 1-2 minutes of execution, master process starts >> to increase it's memory allocation and network traffic becomes low. >> > > > > >> > >> > This memory allocation & network traffic slow down >> continues until fail of MPI, >> > > > > >> > >> > without core file save. >> > > > > >> > >> > My program doesn't allocate memory. Can you please >> explain this behaviour. >> > > > > >> > >> > How can I cause MPI to stop sending slaves if Master >> can't serve such traffic, instead of memory allocation and fail? >> > > > > >> > >> > >> > > > > >> > >> > >> > > > > >> > >> > Thank you, >> > > > > >> > >> > Anatoly. >> > > > > >> > >> > >> > > > > >> > >> > P.S. >> > > > > >> > >> > On my stand alone test, I simulate similar behaviour, >> but with single thread on each process (master & hosts). >> > > > > >> > >> > When I start stand alone test, master stops slaves >> until it completes accumulated data processing and MPI doesn't increase >> memory allocation. >> > > > > >> > >> > When Master is free slaves continue to send data. >> > > > > >> > >> > _______________________________________________ >> > > > > >> > >> > discuss mailing list discuss(a)mpich.org >> > > > > >> > >> > To manage subscription options or unsubscribe: >> > > > > >> > >> > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > >> >> > > > > >> > >> _______________________________________________ >> > > > > >> > >> discuss mailing list discuss(a)mpich.org >> > > > > >> > >> To manage subscription options or unsubscribe: >> > > > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > >> >> > > > > >> > >> _______________________________________________ >> > > > > >> > >> discuss mailing list discuss(a)mpich.org >> > > > > >> > >> To manage subscription options or unsubscribe: >> > > > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > > _______________________________________________ >> > > > > >> > > discuss mailing list discuss(a)mpich.org >> > > > > >> > > To manage subscription options or unsubscribe: >> > > > > >> > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > >> > > > > >> > -- >> > > > > >> > Pavan Balaji >> > > > > >> > http://www.mcs.anl.gov/~balaji >> > > > > >> > >> > > > > >> > _______________________________________________ >> > > > > >> > discuss mailing list discuss(a)mpich.org >> > > > > >> > To manage subscription options or unsubscribe: >> > > > > >> > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > >> > > > > >> > >> > > > > >> > _______________________________________________ >> > > > > >> > discuss mailing list discuss(a)mpich.org >> > > > > >> > To manage subscription options or unsubscribe: >> > > > > >> > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> >> > > > > >> -- >> > > > > >> Pavan Balaji >> > > > > >> http://www.mcs.anl.gov/~balaji >> > > > > >> >> > > > > >> _______________________________________________ >> > > > > >> discuss mailing list discuss(a)mpich.org >> > > > > >> To manage subscription options or unsubscribe: >> > > > > >> https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> >> > > > > >> >> > > > > >> _______________________________________________ >> > > > > >> discuss mailing list discuss(a)mpich.org >> > > > > >> To manage subscription options or unsubscribe: >> > > > > >> https://lists.mpich.org/mailman/listinfo/discuss >> > > > > > >> > > > > > _______________________________________________ >> > > > > > discuss mailing list discuss(a)mpich.org >> > > > > > To manage subscription options or unsubscribe: >> > > > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > > >> > > > > > _______________________________________________ >> > > > > > discuss mailing list discuss(a)mpich.org >> > > > > > To manage subscription options or unsubscribe: >> > > > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > > > > -- >> > > > > Pavan Balaji >> > > > > http://www.mcs.anl.gov/~balaji >> > > > > >> > > > > _______________________________________________ >> > > > > discuss mailing list discuss(a)mpich.org >> > > > > To manage subscription options or unsubscribe: >> > > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > > >> > > > > _______________________________________________ >> > > > > discuss mailing list discuss(a)mpich.org >> > > > > To manage subscription options or unsubscribe: >> > > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > >> > > > -- >> > > > Pavan Balaji >> > > > http://www.mcs.anl.gov/~balaji >> > > > >> > > > _______________________________________________ >> > > > discuss mailing list discuss(a)mpich.org >> > > > To manage subscription options or unsubscribe: >> > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > > >> > > > >> > > > >> > > > <backtrace2.txt>_______________________________________________ >> > > > discuss mailing list discuss(a)mpich.org >> > > > To manage subscription options or unsubscribe: >> > > > https://lists.mpich.org/mailman/listinfo/discuss >> > > >> > > -- >> > > Pavan Balaji >> > > http://www.mcs.anl.gov/~balaji >> > > >> > > _______________________________________________ >> > > discuss mailing list discuss(a)mpich.org >> > > To manage subscription options or unsubscribe: >> > > https://lists.mpich.org/mailman/listinfo/discuss >> > > >> > > _______________________________________________ >> > > discuss mailing list discuss(a)mpich.org >> > > To manage subscription options or unsubscribe: >> > > https://lists.mpich.org/mailman/listinfo/discuss >> > >> > -- >> > Pavan Balaji >> > http://www.mcs.anl.gov/~balaji >> > >> > _______________________________________________ >> > discuss mailing list discuss(a)mpich.org >> > To manage subscription options or unsubscribe: >> > https://lists.mpich.org/mailman/listinfo/discuss >> > >> > >> > >> > _______________________________________________ >> > discuss mailing list discuss(a)mpich.org >> > To manage subscription options or unsubscribe: >> > https://lists.mpich.org/mailman/listinfo/discuss >> >> -- >> Pavan Balaji >> http://www.mcs.anl.gov/~balaji >> >> _______________________________________________ >> discuss mailing list discuss(a)mpich.org >> To manage subscription options or unsubscribe: >> https://lists.mpich.org/mailman/listinfo/discuss >> > >

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Re: [mpich-discuss] MPI memory allocation.
by Anatoly G 28 Dec '13

28 Dec '13

Good morning. I hope that I understand you. I changed my test program to print network rate (not real network rate, but pure data rate after finish each send or receive). My application fails before finishing execution. I attach my program, and the results. No core file created. I use unlimit option, then fails of my programs cause core file creation. execute command: mpiexec.hydra -genvall -f MpiConfigMachines1.txt -launcher=rsh -n 10 /home/anatol-g/Grape/release_under_constr_MPI_tests_quantum/bin/linux64/rhe6/g++4.4.6/debug/mpi_rcv_any_multithread 100000 1000000 -1 -1 1 out Can you please advice. I completely don't understand why program fails. If anything is not clear, please reply and I will try to complete my explanation. Regards, Anatoly. On Wed, Dec 25, 2013 at 6:38 PM, Pavan Balaji <balaji(a)mcs.anl.gov> wrote: > > I have no idea what I need to do with your benchmark since you are relying > on an external tool to give performance debugging information. FWIW, there > will be a memory increase in MPI_Init. That’s expected and not bad. If > you post a bunch of isends, some of them get buffered locally, while others > have to wait for the necessary flow-control. So it might look like your > network performance has dropped. Again, this is expected. I don’t know if > these are what you are seeing or if it’s a different problem. But I can’t > tell from your benchmark. > > It might be easier for us if your application does internal profiling of > memory and communication and printed it out directly. That way, I know > what you are measuring more accurately. > > — Pavan > > On Dec 23, 2013, at 7:19 PM, Anatoly G <anatolyrishon(a)gmail.com> wrote: > > > Hi. > > Do you need more info to reproduce problem? > > > > Anatoly. > > > > > > On Sun, Dec 22, 2013 at 7:54 AM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > Good morning Pavan. > > Do you see process memory raise & network throughput low behavior? > > > > Anatoly. > > > > > > On Thu, Dec 19, 2013 at 7:09 PM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > No. You can see memory increase using monitor like "qps", or any other. > > The stack trace that I send I get when I stop my real program (not > simulation) with TotalView debugger. > > if you monitor network traffic, you will see network speed which becomes > low until it reaches almost 0. > > > > Anatoly. > > > > > > On Thu, Dec 19, 2013 at 5:16 PM, Pavan Balaji <balaji(a)mcs.anl.gov> > wrote: > > > > Are you printing it out? > > > > — Pavan > > > > On Dec 19, 2013, at 10:51 PM, Anatoly G <anatolyrishon(a)gmail.com> wrote: > > > > > Can you please remove comment from section > > > /* > > > // swap tag & enter blocked recv > > > MPI_Status stat; > > > tags[slaveIdx] = (tags[slaveIdx] == TAG1) ? TAG2 : TAG1; > > > MPI_Recv(RcvBufs[slaveIdx], BUF_SZ, MPI::CHAR, slaveRank, > tags[slaveIdx], MPI_COMM_WORLD, &stat); > > > > > > ++SlavesRcvIters[slaveIdx]; > > > */ > > > > > > And then run it. > > > Do you see memory allocation increase? > > > > > > Regards, > > > Anatoly. > > > > > > > > > On Thu, Dec 19, 2013 at 4:29 PM, Pavan Balaji <balaji(a)mcs.anl.gov> > wrote: > > > > > > I’m not sure what I should look for. I ran the program and it > completed fine. > > > > > > — Pavan > > > > > > On Dec 19, 2013, at 7:16 PM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > > > > Good afternoon. > > > > My program enters a lot to attached stack functions. > > > > Can you please explain if it's ok? > > > > Did you success to execute simulation from previous mail. > > > > Did you see the memory raise when MPI_Recv not in comments? > > > > > > > > Regards, > > > > Anatoly. > > > > > > > > > > > > On Thu, Dec 12, 2013 at 9:36 PM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > Hi. > > > > Finally, I got an additional info. > > > > I build short simulation of my real application. > > > > > > > > The short description of real scenario. > > > > I have Master + N slaves. Each slave sends to Master 2 types of > messages: > > > > • constant length message with predefined fields (one of it's > fields is length of second message). > > > > • second message - length of this message each time is > different and passed in first message. > > > > Master should use MPI_Irecv commands, in order to be tolerant to > slaves failure (blocked MPI_Recv is blocking Master in the failure case). > > > > Master executes MPI_Irecv to each slave with buffer size equal to > the constant size of first message type. After receiving first type of > message, Master allocates expected buffer for second message and performs > receive too. This happens in endless loop for each slaves. I use > MPI_Waitany to monitor all receives. > > > > In order to separate messages Master & slaves use different tags (as > ids) for first & second messages. > > > > > > > > Simulation description: > > > > All passed buffers (first & second) have the same size. > > > > Slave (SndSyncSlave) sends messages and swaps 2 tags between them > (like 2 types of messages, but second one has constant size too). > > > > Master routine (Rcv_WaitAny function) executes MPI_Irecv for first > message, and after receive executes MPI_Irecv for the second one. > > > > > > > > In this scenario: 5 processes works fine, but if I execute 20 > processes and remove comment from line "usleep(200000)" I see 800 Mbit/s > on network at the test beginning, but after 1-2 second network speed become > 200-300Kbit/s and not increased back any more. > > > > > > > > If I add MPI_Recv block in Master (remove comment from "MPI_Recv" > and line around) I see that Master starts increase memory as my real > application, but again on 5 processes this not happens. This is scenario > used in my real application. > > > > > > > > Command line: mpiexec.hydra -genvall -f MpiConfigMachines.txt > -launcher=ssh -n 20 mpi_rcv_any_multithread 100000 1000000 out > > > > > > > > where > > > > 100000 - number of sends from each slave > > > > 1000000 - scale to separate input from each scale (used for debug > only) > > > > out - prefix of output file. Each process produce out_"rank".txt > file. > > > > > > > > MpiConfigMachines.txt - configuration file for my computers, 2 > computers back to back 1 Gbit/s network. > > > > > > > > > > > > Can you please test this case, and give me yours suggestions. > > > > > > > > Thank you, > > > > Anatoly. > > > > > > > > > > > > > > > > On Mon, Dec 9, 2013 at 9:55 PM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > Yes, I understand that. I"ll try to make my stand alone test closer > to real application. Thank you. > > > > > > > > > > > > On Mon, Dec 9, 2013 at 9:31 PM, Pavan Balaji <balaji(a)mcs.anl.gov> > wrote: > > > > > > > > It sounds like MPICH is working correctly. Without a test case, > it’s unfortunately quite hard for us to even know what to look for. It’s > also possible that there’s a bug in your code which might be causing some > bad behavior. > > > > > > > > — Pavan > > > > > > > > On Dec 9, 2013, at 1:27 PM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > > > > > > Yes, I"m actually need Fault tolerance, and it was the main reason > for choosing MPICH2. I use fault tolerance for unpredictable bugs in the > future. My system should survive partially. But in the regular case I just > need full performance. I"m suspect that I don't use MPI correctly, but on > slow rate everything works fine. The fail caused by increasing rate of > MPI_Isend or increasing data buffer size. I didn't find yet any strong > dependence, only main stream. > > > > > > > > > > Unfortunately I have a complex system which has a number of > threads in each process. Part of the threads use different communicators. > > > > > > > > > > I try to simulate the same MPI behavior in simple stand alone > test, but stand alone test works fine. It shows a full network performance, > when I slow down master (on stand alone test), all slaves are stopped too > and are waiting for master to continue. Can I open any MPICH log to send > you the results? > > > > > > > > > > > > > > > On Mon, Dec 9, 2013 at 8:10 PM, Pavan Balaji <balaji(a)mcs.anl.gov> > wrote: > > > > > > > > > > Do you actually need Fault Tolerance (one of your previous emails > seemed to indicate that)? > > > > > > > > > > It sounds like there a bug in either your application or in the > MPICH stack and you are trying to trace that down, and don’t really care > about fault tolerance. Is that a correct assessment? > > > > > > > > > > Do you have a simplified program that reproduces this error, that > we can try? > > > > > > > > > > — Pavan > > > > > > > > > > On Dec 9, 2013, at 11:44 AM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > > > > > > > > No. Hardware is Ok. Master process allocates memory (check with > MemoryScape doesn't show any sufficient memory allocation in my code). Then > network traffic become low, and then Master process crashes w/o saving core > file. I have unlimited size of core files. The same fail (w/o core) I see > when I call MPI_Abort, but I don't call it. > > > > > > > > > > > > > > > > > > On Mon, Dec 9, 2013 at 7:28 PM, Wesley Bland <wbland(a)mcs.anl.gov> > wrote: > > > > > > Are you actually seeing hardware failure or is your code just > crashing? It's odd that one specific process would fail so often in the > same way if it were a hardware problem. > > > > > > > > > > > > Thanks, > > > > > > Wesley > > > > > > > > > > > > On Dec 9, 2013, at 11:15 AM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > > > > > > > > >> One more interesting fact. Each time I have a failure, the > fails only master process, but slaves are still exists together with > mpiexec.hydra. I thought that slaves should fail too, but slaves are live. > > > > > >> > > > > > >> > > > > > >> On Mon, Dec 9, 2013 at 10:30 AM, Anatoly G < > anatolyrishon(a)gmail.com> wrote: > > > > > >> I configure MPICH-3.1rc2 build w/o "so" files. But instead of > MPICH2 & MPICH-3.0.4 I get so files. What should I change in configure line > to link MPI with my application statically. > > > > > >> > > > > > >> > > > > > >> > > > > > >> On Mon, Dec 9, 2013 at 9:47 AM, Pavan Balaji < > balaji(a)mcs.anl.gov> wrote: > > > > > >> > > > > > >> Can you try mpich-3.1rc2? There were several fixes for this in > this version and it’ll be good to try that out before we go digging too far > into this. > > > > > >> > > > > > >> — Pavan > > > > > >> > > > > > >> On Dec 9, 2013, at 1:46 AM, Anatoly G <anatolyrishon(a)gmail.com> > wrote: > > > > > >> > > > > > >> > With MPICH - 3.0.4 the situation repeated. It looks like MPI > allocates memory for messages. > > > > > >> > Can you please advice about scenario when MPI or may be TCP > under MPI allocates memory due to high transfer rate? > > > > > >> > > > > > > >> > > > > > > >> > On Mon, Dec 9, 2013 at 9:32 AM, Anatoly G < > anatolyrishon(a)gmail.com> wrote: > > > > > >> > Thank you very much. > > > > > >> > Issend - is not so good, It can't support me Fault tolerance. > If slave process fails, the master stall. > > > > > >> > I tried mpich-3.0.4 with hydra-3.0.4 but my program which > uses MPI Fault tolerance doesn't recognize failure of slave process, but > recognizes failure with MPICH2. May be you can suggest solution? > > > > > >> > I tried to use hydra from MPICH2 but link my program with > MPICH3. This combination recognizes failures, but I"m not sure that such > combination is stable enough. > > > > > >> > Can you please advice? > > > > > >> > Anatoly. > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > On Sat, Dec 7, 2013 at 5:20 PM, Pavan Balaji < > balaji(a)mcs.anl.gov> wrote: > > > > > >> > > > > > > >> > As much as I hate saying this — some people find it easier to > think of it as “MPICH3”. > > > > > >> > > > > > > >> > — Pavan > > > > > >> > > > > > > >> > On Dec 7, 2013, at 7:37 AM, Wesley Bland <wbland(a)mcs.anl.gov> > wrote: > > > > > >> > > > > > > >> > > MPICH is just the new version of MPICH2. We renamed it when > we went past version 3.0. > > > > > >> > > > > > > > >> > > On Dec 7, 2013, at 3:55 AM, Anatoly G < > anatolyrishon(a)gmail.com> wrote: > > > > > >> > > > > > > > >> > >> Ok. I"ll try both Issend, and next step to upgrade MPICH > to 3.0.4. > > > > > >> > >> I thought before that MPICH & MPICH2 are two different > branches, when MPICH2 partially supports Fault tolerance, but MPICH not. > Now I understand, that I was wrong and MPICH2 is just main version of MPICH. > > > > > >> > >> > > > > > >> > >> Thank you very much, > > > > > >> > >> Anatoly. > > > > > >> > >> > > > > > >> > >> > > > > > >> > >> > > > > > >> > >> On Thu, Dec 5, 2013 at 11:01 PM, Rajeev Thakur < > thakur(a)mcs.anl.gov> wrote: > > > > > >> > >> The master is receiving too many incoming messages than it > can match quickly enough with Irecvs. Try using MPI_Issend instead of > MPI_Isend. > > > > > >> > >> > > > > > >> > >> Rajeev > > > > > >> > >> > > > > > >> > >> On Dec 5, 2013, at 2:58 AM, Anatoly G < > anatolyrishon(a)gmail.com> wrote: > > > > > >> > >> > > > > > >> > >> > Hello. > > > > > >> > >> > I"m using MPICH2 1.5. > > > > > >> > >> > My system contains master and 16 slaves. > > > > > >> > >> > System uses number of communicators. > > > > > >> > >> > The single communicator used for below scenario: > > > > > >> > >> > Each slave sends non-stop 2Kbyte data buffer using > MPI_Isend and waits using MPI_Wait. > > > > > >> > >> > Master starts with MPI_Irecv to each slave > > > > > >> > >> > Then in endless loop: > > > > > >> > >> > MPI_Waitany and MPI_Irecv on rank returned by > MPI_Waitany. > > > > > >> > >> > > > > > > >> > >> > Another communicator used for broadcast communication > (commands between master + slaves), > > > > > >> > >> > but it's not used in parallel with previous communicator, > > > > > >> > >> > only before or after data transfer. > > > > > >> > >> > > > > > > >> > >> > The system executed on two computers linked by 1Gbit/s > Ethernet. > > > > > >> > >> > Master executed on first computer, all slaves on other > one. > > > > > >> > >> > Network traffic is ~800Mbit/s. > > > > > >> > >> > > > > > > >> > >> > After 1-2 minutes of execution, master process starts to > increase it's memory allocation and network traffic becomes low. > > > > > >> > >> > This memory allocation & network traffic slow down > continues until fail of MPI, > > > > > >> > >> > without core file save. > > > > > >> > >> > My program doesn't allocate memory. Can you please > explain this behaviour. > > > > > >> > >> > How can I cause MPI to stop sending slaves if Master > can't serve such traffic, instead of memory allocation and fail? > > > > > >> > >> > > > > > > >> > >> > > > > > > >> > >> > Thank you, > > > > > >> > >> > Anatoly. > > > > > >> > >> > > > > > > >> > >> > P.S. > > > > > >> > >> > On my stand alone test, I simulate similar behaviour, > but with single thread on each process (master & hosts). > > > > > >> > >> > When I start stand alone test, master stops slaves until > it completes accumulated data processing and MPI doesn't increase memory > allocation. > > > > > >> > >> > When Master is free slaves continue to send data. > > > > > >> > >> > _______________________________________________ > > > > > >> > >> > discuss mailing list discuss(a)mpich.org > > > > > >> > >> > To manage subscription options or unsubscribe: > > > > > >> > >> > https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > >> > > > > > >> > >> _______________________________________________ > > > > > >> > >> discuss mailing list discuss(a)mpich.org > > > > > >> > >> To manage subscription options or unsubscribe: > > > > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > >> > > > > > >> > >> _______________________________________________ > > > > > >> > >> discuss mailing list discuss(a)mpich.org > > > > > >> > >> To manage subscription options or unsubscribe: > > > > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > > _______________________________________________ > > > > > >> > > discuss mailing list discuss(a)mpich.org > > > > > >> > > To manage subscription options or unsubscribe: > > > > > >> > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > > > > > > >> > -- > > > > > >> > Pavan Balaji > > > > > >> > http://www.mcs.anl.gov/~balaji > > > > > >> > > > > > > >> > _______________________________________________ > > > > > >> > discuss mailing list discuss(a)mpich.org > > > > > >> > To manage subscription options or unsubscribe: > > > > > >> > https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > > > > > > >> > > > > > > >> > _______________________________________________ > > > > > >> > discuss mailing list discuss(a)mpich.org > > > > > >> > To manage subscription options or unsubscribe: > > > > > >> > https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > > > > > >> -- > > > > > >> Pavan Balaji > > > > > >> http://www.mcs.anl.gov/~balaji > > > > > >> > > > > > >> _______________________________________________ > > > > > >> discuss mailing list discuss(a)mpich.org > > > > > >> To manage subscription options or unsubscribe: > > > > > >> https://lists.mpich.org/mailman/listinfo/discuss > > > > > >> > > > > > >> > > > > > >> _______________________________________________ > > > > > >> discuss mailing list discuss(a)mpich.org > > > > > >> To manage subscription options or unsubscribe: > > > > > >> https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > > > > > _______________________________________________ > > > > > > discuss mailing list discuss(a)mpich.org > > > > > > To manage subscription options or unsubscribe: > > > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > > > > > _______________________________________________ > > > > > > discuss mailing list discuss(a)mpich.org > > > > > > To manage subscription options or unsubscribe: > > > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > > > -- > > > > > Pavan Balaji > > > > > http://www.mcs.anl.gov/~balaji > > > > > > > > > > _______________________________________________ > > > > > discuss mailing list discuss(a)mpich.org > > > > > To manage subscription options or unsubscribe: > > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > > > _______________________________________________ > > > > > discuss mailing list discuss(a)mpich.org > > > > > To manage subscription options or unsubscribe: > > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > -- > > > > Pavan Balaji > > > > http://www.mcs.anl.gov/~balaji > > > > > > > > _______________________________________________ > > > > discuss mailing list discuss(a)mpich.org > > > > To manage subscription options or unsubscribe: > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > > > > > > > > > <backtrace2.txt>_______________________________________________ > > > > discuss mailing list discuss(a)mpich.org > > > > To manage subscription options or unsubscribe: > > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > -- > > > Pavan Balaji > > > http://www.mcs.anl.gov/~balaji > > > > > > _______________________________________________ > > > discuss mailing list discuss(a)mpich.org > > > To manage subscription options or unsubscribe: > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > _______________________________________________ > > > discuss mailing list discuss(a)mpich.org > > > To manage subscription options or unsubscribe: > > > https://lists.mpich.org/mailman/listinfo/discuss > > > > -- > > Pavan Balaji > > http://www.mcs.anl.gov/~balaji > > > > _______________________________________________ > > discuss mailing list discuss(a)mpich.org > > To manage subscription options or unsubscribe: > > https://lists.mpich.org/mailman/listinfo/discuss > > > > > > > > _______________________________________________ > > discuss mailing list discuss(a)mpich.org > > To manage subscription options or unsubscribe: > > https://lists.mpich.org/mailman/listinfo/discuss > > -- > Pavan Balaji > http://www.mcs.anl.gov/~balaji > > _______________________________________________ > discuss mailing list discuss(a)mpich.org > To manage subscription options or unsubscribe: > https://lists.mpich.org/mailman/listinfo/discuss >

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Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely
by Madhawa Bandara 28 Dec '13

28 Dec '13

Thank you Sent from my Windows phone -----Original Message----- From: "Pavan Balaji" <balaji(a)mcs.anl.gov> Sent: ‎12/‎26/‎2013 13:14 To: "discuss(a)mpich.org" <discuss(a)mpich.org> Subject: Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely On Dec 26, 2013, at 1:38 AM, Madhawa Bandara <madawa911(a)gmail.com> wrote: > Are you suggesting using non-blocking send/recv? On the master process, yes. On the slave, it won't matter. An alternative is to use MPI_ANY_SOURCE receive, but nonblocking is better. -- Pavan Balaji http://www.mcs.anl.gov/~balaji _______________________________________________ discuss mailing list discuss(a)mpich.org To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

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Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely
by Madhawa Bandara 26 Dec '13

26 Dec '13

Yeah I understand. Thank you very much Sent from my Windows phone -----Original Message----- From: "Pavan Balaji" <balaji(a)mcs.anl.gov> Sent: ‎12/‎26/‎2013 13:14 To: "discuss(a)mpich.org" <discuss(a)mpich.org> Subject: Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely On Dec 26, 2013, at 1:38 AM, Madhawa Bandara <madawa911(a)gmail.com> wrote: > Are you suggesting using non-blocking send/recv? On the master process, yes. On the slave, it won't matter. An alternative is to use MPI_ANY_SOURCE receive, but nonblocking is better. -- Pavan Balaji http://www.mcs.anl.gov/~balaji _______________________________________________ discuss mailing list discuss(a)mpich.org To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

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Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely
by Pavan Balaji 26 Dec '13

26 Dec '13

On Dec 26, 2013, at 1:38 AM, Madhawa Bandara <madawa911(a)gmail.com> wrote: > Are you suggesting using non-blocking send/recv? On the master process, yes. On the slave, it won't matter. An alternative is to use MPI_ANY_SOURCE receive, but nonblocking is better. -- Pavan Balaji http://www.mcs.anl.gov/~balaji

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Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely
by Madhawa Bandara 26 Dec '13

26 Dec '13

Are you suggesting using non-blocking send/recv? Sent from my Windows phone -----Original Message----- From: "Pavan Balaji" <balaji(a)mcs.anl.gov> Sent: ‎12/‎26/‎2013 12:29 To: "discuss(a)mpich.org" <discuss(a)mpich.org> Subject: Re: [mpich-discuss] MPI_Send/MPI_Recv - getting delayed indeffinitely On Dec 25, 2013, at 8:50 PM, Madhawa Bandara <madawa911(a)gmail.com> wrote: > Thanks for the response. Actually I was using float as the data type in the program whereas MPI_DOUBLE is used in communication.. That has been the reason Ok, great. > Serializing means assigning a tag? Not exactly. Serializing is probably not the correct terminology here. The problem is what I described in my response. worker2 might send the message before worker1, in which case, it will have to wait for the master to receive worker1’s message and then process its message. If it’s not causing performance degradation for you, don’t worry about it. — Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji _______________________________________________ discuss mailing list discuss(a)mpich.org To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

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