I am doing some tests with mpich in a dual-processor SMP server.

Now I use mpich-3.0.3, I also use knem for accelerating intra-node communication.

The channel I used is nemesis:tcp, and nemesis-local-lmt=knem.

But when I use osu_benchmarks to do the bandwidth test, osu_bw will segment

fault at the 2MB, which is the default value of MPICH_NEM_LMT_DMA_THRESHOLD.

It seems when DMA channel in knem is used, the segment fault occurs.

When I set MPICH_NEM_LMT_DMA_THRESHOLD to a smaller value, such as

131072, osu_bw will segment fault at 131072.

I also test NAS Parallell Benchmark. I noticed when DMA channel in knem is used,

sometimes the NPB tests will be freezed after running for a while.

In the attachment, I list some config and core dump files.

Did anyone met or solved the similar problems.

Thanks for your help.