Server Gurus Discussions

[mrmeswani]

I have a system with AMD EPYC 7551 32-Core Processor running Ubuntu and with AMDuProf installed

I have been trying to collect L3 counters but i get the following message

Running the example cmd in uProf User guide

AMDuProfCLI collect -e event=timer,interval=1 -e event=0xb001,umask=0x80,slicemask=0xF,threadmask=0xFF -a -d 10

There was a problem configuring the L3 profile event(0xb001).

Also tried the command posted in another discussion thread

./AMDuProfCLI collect -e event=timer,interval=1 -e event=0xb006,umask=0x01,slicemask=0xF,threadmask=0xFF -a -d 10 -o /tmp/out

There was a problem configuring the L3 profile event(0xb006).

Why is this counter not working ? I am running as root.

[linux_monkey]

Recall that EPYC implements multiple L3 caches where each L3 is part of a Compute Complex (CCX). When you are collecting thread counts you need to specify which CCX for which you want to collect L3 counts.

Please try a threadmask where the only set bit is the first CPU in the CCX you wish to profile (e.g. CPU 0 for CCX0 on die 0 socket 0, CPU 4 on a 32 core part for CCX1 on die 0 socket 0). The lstopo program from the Portable Hardware Locality library (hwloc) on Linux is handy for showing you which CPUs are sharing which L3.

Not 100% sure this is your problem, but even if not, this may be helpful.

-Monkey

[mrmeswani]

I tried with different threadmasks like Ox01 , but I still get the same error. I want to profile and L3 miss counts from all slices, are you able to collect L3 misses on your system, if so can you share the profiling command?

[swarup]

L3 profiling is not yet supported on Linux platforms, so far supported only on Windows platforms. This is in our pipeline and should be available in the future releases.

[mrmeswani]

What counters are functional in Linux? Can we also know which counters are DF ?

[swarup]

L3/DF counters are not supported on Linux yet.To get the list of supported events on a system, please use the command "./AMDuProfCLI collect --list cpu-events". The list of supported events might be different on different systems/platforms.