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Re: [codes-ross-users] CODES LP Design Question
by Phil Carns 14 May '15

14 May '15

What I described in this thread turned out to be a bad idea. The problem with handing off a function pointer is that the target LP (thing2 in the example below) might not be on the same process as the caller (thing1), so in the general case it isn't safe to let it hang onto a function pointer to issue the completion event. The lsm/local-storage-model API has this same issue (a higher level models want to hand control off to a disk model and then just get proceed with with its own work once the disk access is complete). LSM solves this safely from a technical point of view by providing functions for the caller to allocate an appropriate event, and letting the caller specify it's own event struct that will be handed back on completion. This is safe regardless of how your LPs are organized, but it still bugs me a little, though, because a) it looks burly in the code and b) the target LP doesn't have a way to pass results back in the completion event. Anyway, I'll putter around with this and share if I come up with something cleaner, but I wanted to at least respond to this thread as a warning in the mean time :) thanks, -Phil On 04/08/2015 10:44 AM, Carns, Philip H. wrote: > I've never tried to modularize steps like this in a single LP, but it is > a little similar to some cross-LP scenarios I've run into before. Here > comes a long-winded example :) > > Imagine you have two LPs (that run on the same simulated node), called > thing1 and thing2. You want the thing1 procedure to invoke thing2, and > then for thing1 to continue once thing2 is done. > > If I were to do this now I think I would set it up like this. Assume > that thing1 and thing2 each have their own .c and .h files. > > thing2.h has this prototype: void start_thing2(lp, gid, completion_fn_ptr); > > This function will construct and send an event to the thing2 LP > (identified by the gid argument) to kick off whatever it is going to > do. This function will be executed within a thing1 LP event handler, > but the definition of the function is in thing2.c. The purpose of this > arrangement is to let thing1 send an event to thing2 without having > access to thing2's event structure definition. As long as you keep the > API stable then thing2.c can do whatever it needs to do in terms of > refactoring its event structure without perturbing thing1. > > The lp argument is the lp pointer for the *calling* LP, and is probably > needed to allocate a new event. > > The completion_fn_ptr is a function pointer to a function defined by the > caller (thing1 in this case) that sends an event back to the original > LP. This is the mechanism for thing2 to tell thing1 it is done so that > thing1 can continue operation. Since it is an opaque function pointer, > thing2 remains oblivious to the event structure definition of thing1 (or > even what kind of LP thing1 is). You can make the completion_fn_ptr > signature anything that you like, so if thing2 has some result to report > back, then it can be passed as an argument to that function and stuffed > into the event that heads back to thing1. > > Of course you can also add whatever arbitrary arguments you want to > start_thing2() to pass input parameters it needs to start whatever > thing2 is doing. Those would get stuffed into the event destined for > thing2. > > Unfortunately I haven't actually done this so I don't have an example. > My thinking on how to organize this has evolved over time and I haven't > gotten around to trying this particular permutation :) I've done > something very similar except for the function pointer; I have a few > examples have an explicitly defined function that jumps back from thing2 > to thing1. That works fine, but it is bad news if you want more than > one type of LP to be able to call thing2. > > A related theme here is that I'm a fan (possibly in the minority on > this) of splitting up different complex procedures that happen on the > same simulated node into separate LPs. As long as you have them share > node resources (NIC, storage, etc.) then the net result is the same in > terms of the simulation outcome. The positive is that you don't have > event handler explosion (big switch statements to handle different > cases). The negative is that you have to jump between these LPs by > sending events with small timestamps. Once you start doing that, then > parallel conservative execution is practically out of the question; you > have to do serial execution or parallel optimistic execution to handle > those extra small events in a reasonable way. > > This might be overkill for your scenario, but I thought I would throw it > out there. I wanted to collect my thoughts on this anyway. In general > I don't think there is any particular way around this without juggling > callbacks and such; really the best thing you can hope for right now is > to minimize entanglement between different LP types in your code. > > -Phil > > On 04/08/2015 06:47 AM, Ross, Robert B. wrote: >> I think the way to think about this is that the event payload carries the state associated with the operation and gets passed around between LPs as needed to simulate the steps. If you do this right, there shouldn't be local LP state associated with the operation -- everything is in the event payload that is needed. >> >> There might be state at LPs associated with the LP itself, such as what objects exist or what names are in the namespace. Or not, if you are just assuming things exist for instance. >> >> John, Phil, and/or Misbah may need to correct me...of course. >> >> -- Rob >> >>> On Apr 7, 2015, at 4:09 PM, Jenkins, Jonathan P. <jenkins(a)mcs.anl.gov> wrote: >>> >>> Hi Joe, >>> >>> So if I understand right, the context is you want to simulate some POSIX >>> operations of interest, such as mkdir, and that the client is capable of >>> performing the stat (the lookup) using purely local information (hence the >>> self-event)? >>> >>> In general, it's useful to think of events in these systems as RPC calls, >>> where the event structure you are setting up contains the parameters, and >>> there are corresponding return parameters that the calling LP expects to >>> receive. In this frame of thought, both RPC calls and returns issue a >>> discrete event. In your example, you could have your "mkdir" RPC event >>> handler perform an additional "lookup/stat" RPC to check the path's >>> existence, and upon receiving the "return" event, either make the >>> directory or fail. >>> >>> Unfortunately, event-driven programming more-or-less necessitates >>> callback-heavy code, which can be quite awkward in some contexts. We've >>> talked in the past about ways to at least standardize the way we do this >>> in the context of CODES, but nothing has materialized as of yet. >>> >>> Hope that helps. Something tells me that the assumption about clients >>> being capable of performing metadata operations without outside >>> interaction with e.g. a storage server is not quite right, though I could >>> be misunderstanding. >>> >>> Thanks, >>> John >>> >>>> On 4/7/15, 3:43 PM, "Joe Scott" <tscott2(a)g.clemson.edu> wrote: >>>> >>>> Hello All, >>>> >>>> I am having a hard time wrapping myself around the programming paradigm >>>> here, and I wonder if you might offer some guidance on a better way to >>>> use CODES. >>>> >>>> So I am trying to process these higher level tasks (POSIX tasks like >>>> mkdir) by launching the subevents as separate processes. >>>> >>>> The specific case that is tying me in knots is a user issuing a mkdir. >>>> It launches the mkdir event handler, which needs to perform a lookup on >>>> the path of the mkdir. >>>> >>>> So I need to send an event from this client LP to itself to perform the >>>> lookup. But I also need the lookup, upon completion, to relaunch the >>>> mkdir task. >>>> >>>> Speaking it over with some of my lab mates, they seem to think I am >>>> either overthinking it or trying to use the wrong tool for the job. >>>> >>>> Is this a usecase you guys are familiar with? Can you shed some light on >>>> this situation? >>>> >>>> I feel like there should be a way to do this without getting into >>>> callback/completion function hell. >>>> >>>> Thanks, >>>> Joe Scott >>>> Clemson University >>>> _______________________________________________ >>>> codes-ross-users mailing list >>>> codes-ross-users(a)lists.mcs.anl.gov >>>> https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users >>> _______________________________________________ >>> codes-ross-users mailing list >>> codes-ross-users(a)lists.mcs.anl.gov >>> https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users >> _______________________________________________ >> codes-ross-users mailing list >> codes-ross-users(a)lists.mcs.anl.gov >> https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users > _______________________________________________ > codes-ross-users mailing list > codes-ross-users(a)lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users

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CODES 0.4.0 released!
by Jenkins, Jonathan P. 06 May '15

06 May '15

Hi all, CODES 0.4.0 has been released! You can find the release at http://press3.mcs.anl.gov/codes/downloads/ . Notable in this release include a large cleanup/refactoring of the codebase, improvements to error handling, numerous bugfixes, and improved documentation. Additionally, the workload generator API for IO and networking has been merged, though the overall implementation is still in experimental phase. For the full release announcement including the changelog, please visit: http://www.mcs.anl.gov/research/projects/codes/2015/05/06/codes-0-4-0-relea sed/ Thanks, John

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Re: [codes-ross-users] CODES LP Design Question
by Phil Carns 08 Apr '15

08 Apr '15

I've never tried to modularize steps like this in a single LP, but it is a little similar to some cross-LP scenarios I've run into before. Here comes a long-winded example :) Imagine you have two LPs (that run on the same simulated node), called thing1 and thing2. You want the thing1 procedure to invoke thing2, and then for thing1 to continue once thing2 is done. If I were to do this now I think I would set it up like this. Assume that thing1 and thing2 each have their own .c and .h files. thing2.h has this prototype: void start_thing2(lp, gid, completion_fn_ptr); This function will construct and send an event to the thing2 LP (identified by the gid argument) to kick off whatever it is going to do. This function will be executed within a thing1 LP event handler, but the definition of the function is in thing2.c. The purpose of this arrangement is to let thing1 send an event to thing2 without having access to thing2's event structure definition. As long as you keep the API stable then thing2.c can do whatever it needs to do in terms of refactoring its event structure without perturbing thing1. The lp argument is the lp pointer for the *calling* LP, and is probably needed to allocate a new event. The completion_fn_ptr is a function pointer to a function defined by the caller (thing1 in this case) that sends an event back to the original LP. This is the mechanism for thing2 to tell thing1 it is done so that thing1 can continue operation. Since it is an opaque function pointer, thing2 remains oblivious to the event structure definition of thing1 (or even what kind of LP thing1 is). You can make the completion_fn_ptr signature anything that you like, so if thing2 has some result to report back, then it can be passed as an argument to that function and stuffed into the event that heads back to thing1. Of course you can also add whatever arbitrary arguments you want to start_thing2() to pass input parameters it needs to start whatever thing2 is doing. Those would get stuffed into the event destined for thing2. Unfortunately I haven't actually done this so I don't have an example. My thinking on how to organize this has evolved over time and I haven't gotten around to trying this particular permutation :) I've done something very similar except for the function pointer; I have a few examples have an explicitly defined function that jumps back from thing2 to thing1. That works fine, but it is bad news if you want more than one type of LP to be able to call thing2. A related theme here is that I'm a fan (possibly in the minority on this) of splitting up different complex procedures that happen on the same simulated node into separate LPs. As long as you have them share node resources (NIC, storage, etc.) then the net result is the same in terms of the simulation outcome. The positive is that you don't have event handler explosion (big switch statements to handle different cases). The negative is that you have to jump between these LPs by sending events with small timestamps. Once you start doing that, then parallel conservative execution is practically out of the question; you have to do serial execution or parallel optimistic execution to handle those extra small events in a reasonable way. This might be overkill for your scenario, but I thought I would throw it out there. I wanted to collect my thoughts on this anyway. In general I don't think there is any particular way around this without juggling callbacks and such; really the best thing you can hope for right now is to minimize entanglement between different LP types in your code. -Phil On 04/08/2015 06:47 AM, Ross, Robert B. wrote: > I think the way to think about this is that the event payload carries the state associated with the operation and gets passed around between LPs as needed to simulate the steps. If you do this right, there shouldn't be local LP state associated with the operation -- everything is in the event payload that is needed. > > There might be state at LPs associated with the LP itself, such as what objects exist or what names are in the namespace. Or not, if you are just assuming things exist for instance. > > John, Phil, and/or Misbah may need to correct me...of course. > > -- Rob > >> On Apr 7, 2015, at 4:09 PM, Jenkins, Jonathan P. <jenkins(a)mcs.anl.gov> wrote: >> >> Hi Joe, >> >> So if I understand right, the context is you want to simulate some POSIX >> operations of interest, such as mkdir, and that the client is capable of >> performing the stat (the lookup) using purely local information (hence the >> self-event)? >> >> In general, it's useful to think of events in these systems as RPC calls, >> where the event structure you are setting up contains the parameters, and >> there are corresponding return parameters that the calling LP expects to >> receive. In this frame of thought, both RPC calls and returns issue a >> discrete event. In your example, you could have your "mkdir" RPC event >> handler perform an additional "lookup/stat" RPC to check the path's >> existence, and upon receiving the "return" event, either make the >> directory or fail. >> >> Unfortunately, event-driven programming more-or-less necessitates >> callback-heavy code, which can be quite awkward in some contexts. We've >> talked in the past about ways to at least standardize the way we do this >> in the context of CODES, but nothing has materialized as of yet. >> >> Hope that helps. Something tells me that the assumption about clients >> being capable of performing metadata operations without outside >> interaction with e.g. a storage server is not quite right, though I could >> be misunderstanding. >> >> Thanks, >> John >> >>> On 4/7/15, 3:43 PM, "Joe Scott" <tscott2(a)g.clemson.edu> wrote: >>> >>> Hello All, >>> >>> I am having a hard time wrapping myself around the programming paradigm >>> here, and I wonder if you might offer some guidance on a better way to >>> use CODES. >>> >>> So I am trying to process these higher level tasks (POSIX tasks like >>> mkdir) by launching the subevents as separate processes. >>> >>> The specific case that is tying me in knots is a user issuing a mkdir. >>> It launches the mkdir event handler, which needs to perform a lookup on >>> the path of the mkdir. >>> >>> So I need to send an event from this client LP to itself to perform the >>> lookup. But I also need the lookup, upon completion, to relaunch the >>> mkdir task. >>> >>> Speaking it over with some of my lab mates, they seem to think I am >>> either overthinking it or trying to use the wrong tool for the job. >>> >>> Is this a usecase you guys are familiar with? Can you shed some light on >>> this situation? >>> >>> I feel like there should be a way to do this without getting into >>> callback/completion function hell. >>> >>> Thanks, >>> Joe Scott >>> Clemson University >>> _______________________________________________ >>> codes-ross-users mailing list >>> codes-ross-users(a)lists.mcs.anl.gov >>> https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users >> _______________________________________________ >> codes-ross-users mailing list >> codes-ross-users(a)lists.mcs.anl.gov >> https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users > _______________________________________________ > codes-ross-users mailing list > codes-ross-users(a)lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/codes-ross-users

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CODES LP Design Question
by Joe Scott 08 Apr '15

08 Apr '15

Hello All, I am having a hard time wrapping myself around the programming paradigm here, and I wonder if you might offer some guidance on a better way to use CODES. So I am trying to process these higher level tasks (POSIX tasks like mkdir) by launching the subevents as separate processes. The specific case that is tying me in knots is a user issuing a mkdir. It launches the mkdir event handler, which needs to perform a lookup on the path of the mkdir. So I need to send an event from this client LP to itself to perform the lookup. But I also need the lookup, upon completion, to relaunch the mkdir task. Speaking it over with some of my lab mates, they seem to think I am either overthinking it or trying to use the wrong tool for the job. Is this a usecase you guys are familiar with? Can you shed some light on this situation? I feel like there should be a way to do this without getting into callback/completion function hell. Thanks, Joe Scott Clemson University

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Help needed in running codes.
by Sughosh Divanji 03 Mar '15

03 Mar '15

Hi, I am trying to use codes for my project and I am new to codes. I have installed codes. Can you provide me a sample hello-world program and instructions on how to run it. I haven't been able to find documentation on how to run the programs and also make files seem to be broken. Thanks, Sughosh ᐧ

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make for codes-base is failing at src/util/codes_mapping.c:483:51
by Sughosh Divanji 23 Feb '15

23 Feb '15

Hi, I am trying to install codes-base-0.3.0. Make is failing with the following error, sughosh@sughosh-Lenovo-G50-45:~/Desktop/IITC/CS597/codes-base-0.3.0/build$ make make all-am make[1]: Entering directory `/home/sughosh/Desktop/IITC/CS597/codes-base-0.3.0/build' CC src/util/codes_mapping.o ../src/util/codes_mapping.c: In function ‘codes_mapping_init’: ../src/util/codes_mapping.c:422:3: warning: passing argument 2 of ‘tw_lp_settype’ discards ‘const’ qualifier from pointer target type [enabled by default] tw_lp_settype(ross_lid, lp_type_lookup(lp_type_name)); ^ In file included from /home/sughosh/Desktop/IITC/CS597/ROSS/install/include/ross.h:195:0, from ../codes/codes.h:11, from ../codes/codes_mapping.h:11, from ../src/util/codes_mapping.c:10: /home/sughosh/Desktop/IITC/CS597/ROSS/install/include/ross-extern.h:97:15: note: expected ‘struct tw_lptype *’ but argument is of type ‘const struct tw_lptype *’ extern void tw_lp_settype(tw_lpid lp, tw_lptype * type); ^ ../src/util/codes_mapping.c: In function ‘codes_mapping_setup_with_seed_offset’: ../src/util/codes_mapping.c:483:51: error: ‘g_tw_rng_max’ undeclared (first use in this function) global_nlps * offset) * g_tw_rng_max + i); ^ ../src/util/codes_mapping.c:483:51: note: each undeclared identifier is reported only once for each function it appears in make[1]: *** [src/util/codes_mapping.o] Error 1 make[1]: Leaving directory `/home/sughosh/Desktop/IITC/CS597/codes-base-0.3.0/build' make: *** [all] Error 2 Please let me know how to fix this. Thanks, Sughosh ᐧ

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Cmake fails with reason "include could not find load file:GetGitRevisionDescription"
by Sughosh Divanji 30 Jan '15

30 Jan '15

Hi all, I am trying to install ROSS and I am following the instructions on " https://github.com/carothersc/ROSS/wiki/Installation". git clone is successful. But cmake fails with following reason: CMake Error at core/CMakeLists.txt:67 (INCLUDE): include could not find load file: GetGitRevisionDescription CMake Error at core/CMakeLists.txt:68 (GET_GIT_HEAD_REVISION): Unknown CMake command "GET_GIT_HEAD_REVISION". -- Configuring incomplete, errors occurred! At first I tried compiling without DROSS_BUILD_MODELS option because the recent changes are yet to be re-integrated in code base. And also, I am getting the same error with DROSS_BUILD_MODELS option as well. Please let me know how to fix this. Thanks, Sughosh ᐧ

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New ROSS Release
by Elsa Gonsiorowski 29 Jan '15

29 Jan '15

Hello ROSS users, A new version of ROSS has just been released! Overall, this latest version of ROSS is smaller and faster than the legacy version. To get the code and the install instructions, visit the repository page: https://github.com/carothersc/ROSS <https://github.com/carothersc/ROSS> For a list of all the changes, check out this page: https://github.com/carothersc/ROSS/wiki/Differences-between-Simplified-ROSS… <https://github.com/carothersc/ROSS/wiki/Differences-between-Simplified-ROSS…> To get a copy of Legacy ROSS, either checkout the “Legacy” tag in Git, or go here: https://github.com/carothersc/ROSS/releases/tag/Legacy <https://github.com/carothersc/ROSS/releases/tag/Legacy> Please let me or the list know if you have any questions. Also, feel free to request features or submit bug reports through our GitHub page: https://github.com/carothersc/ROSS <https://github.com/carothersc/ROSS> Enjoy! Elsa Gonsiorowski

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codes_mapping_setup() seg fault and RNG issue
by Timothy Scott 14 Jan '15

14 Jan '15

Hello All, I am back trying to get a basic model set up in CODES. I am using a variation of doc/heterogenous (ping with two groups and forwarders). I also found that the doc/example_heterogeneous fails in the same way. In codes_mapping_setup_with_seed_offset() called with parameter 0 (from codes_mapping_setup()), tw_define_lps() prints ~/src/ROSS/ross/rand-clcg4.c:289: RNG max streams exceeded: 2 > 1. I found that if I manually g_tw_rng_max to a number greater than 2 in codes_mapping_setup_with_seed_offset() before the tw_define_lps() call, the code runs fine. I can't find any failure caused by this. Is this a bug or am I (and the example) invoking something wrong? Thanks, Joe -- Joe Scott PhD Student Clemson University

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example_heterogeneous broken in doc/
by Joe Scott 22 Dec '14

22 Dec '14

Greetings, I have been trying to wrap my head around building networks and was referring to the example_heterogeneous setup with forwarders. Turns out, example_heterogeneous doesn't seem to work. None of the pings/pongs get delivered. Can anybody point out what is broken in example_heterogeneous? I have tried tracing messages, and I can see that the initial ping gets to the bar forwarders, but when bar forwarders try to forward with 'model_net_event_annotated', something breaks and there is never a PING_RECEIVED event. Thanks, Joe Scott Clemson University

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