| Summary: | Unrecognized instruction CLFLUSHOPT in Intel oneAPI MPI 2021.6 library | ||
|---|---|---|---|
| Product: | [Developer tools] valgrind | Reporter: | f.roeser <f.roeser> |
| Component: | memcheck | Assignee: | Julian Seward <jseward> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | critical | CC: | mark, tom |
| Priority: | NOR | ||
| Version First Reported In: | 3.19.0 | ||
| Target Milestone: | --- | ||
| Platform: | RedHat Enterprise Linux | ||
| OS: | Other | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
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Description
f.roeser@magmasoft.de
2022-07-20 16:13:00 UTC
This is CLFLUSHOPT which valgrind indeed doesn't support. But valgrind also makes sure the cpuid CLFLUSHOPT bit isn't set. So the program really shouldn't use CLFLUSHOPT without checking cpuid says it is supported. *** This bug has been marked as a duplicate of bug 424248 *** Thank you for your answer, is there a possible workaround to get valgrind running? Is there a time schedule for a new valgrind build which fixes this issue? Best regards Frank (In reply to f.roeser@magmasoft.de from comment #3) > Thank you for your answer, is there a possible workaround to get valgrind > running? > Is there a time schedule for a new valgrind build which fixes this issue? Note that this is a bug in your program or the library you are using. Valgrind clearly indicates it doesn't implement CLFLUSHOPT. So your program/library shouldn't use that instruction. Your program will also crash on a processor that doesn't implement that instruction. Valgrind does support CLFLUSH. It looks like CLFLUSHOPT is similar. So it might not be too hard to support it. I found a solution : ) https://github.com/pmem/valgrind/tree/pmem-3.19 With this version we can use valgrind with new Intel MPI 2021.6 Best regards Frank Is this also a forbidden instruction? vex amd64->IR: unhandled instruction bytes: 0x62 0xF1 0x7C 0x48 0x10 0x2 0x49 0x81 0xC0 0x0 vex amd64->IR: REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0 vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0 ==1112423== valgrind: Unrecognised instruction at address 0x1e74d9c0. ==1112423== at 0x1E74D9C0: I_MPI_memcpy_nontemporal_avx512 (in /net/aws1de027/data/repo_cache/mature/intelmpi_rt/2021.6.0/LINUX64_217/lib/libmpi.so.12) I took https://github.com/pmem/valgrind/tree/pmem-3.19 and it worked better than original 3.19 but also fails on some runs : ( No instructions are "forbidden" but some are not supported yet. (In reply to f.roeser@magmasoft.de from comment #6) > Is this also a forbidden instruction? > vex amd64->IR: unhandled instruction bytes: 0x62 0xF1 0x7C 0x48 0x10 0x2 > 0x49 0x81 0xC0 0x0 > vex amd64->IR: REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0 > vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE > vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0 > ==1112423== valgrind: Unrecognised instruction at address 0x1e74d9c0. > ==1112423== at 0x1E74D9C0: I_MPI_memcpy_nontemporal_avx512 (in > /net/aws1de027/data/repo_cache/mature/intelmpi_rt/2021.6.0/LINUX64_217/lib/ > libmpi.so.12) That looks like a avx52 variant of the MOVUPS instruction. Valgrind doesn't support that instruction. Yet see https://bugs.kde.org/show_bug.cgi?id=383010 Your program should first check the CPU supports such instructions before use. > I took https://github.com/pmem/valgrind/tree/pmem-3.19 and it worked better > than original 3.19 but also fails on some runs : ( Have you contacted the pmem valgrind developers to see if they want to contribute their improvements upstream? Hi, Thank you for your answer. The problem occurs in the Intel 2021.6 MPI library. As far as I understand it runs this code path when cpuid returns positive if avx512 is available. Could valgrind emulate cpuid and give a fake response that avy512 is not available? Best regards Frank (In reply to f.roeser@magmasoft.de from comment #9) > Thank you for your answer. The problem occurs in the Intel 2021.6 MPI > library. As far as I understand it runs this code path when cpuid returns > positive if avx512 is available. Could valgrind emulate cpuid and give a > fake response that avy512 is not available? valgrind does emulate cpuid to say that avx512 isn't available. So it must be a bug in the Intel 2021.6 MPI library. That is exactly what we do and why Mark said your program should be checking the CPU capabilities. Hi, Just as an Info: Luckily one can overcome the behavior of the mpi library with a environment variable I_MPI_SHM=bdw_sse or I_MPI_SHM=bdw_avx2 for non avx512 memcopy. I found out searching google someone else had a similar problem with valgrind and avx512 instructions in the Intel mpi library. There the cpu was avx512 ready but it was disabled in bios and somehow the cpuid delivers wrong? outcome so that the Intel mpi lib took the avx512 path. Best regards Frank |