LLC-* events not working on sandybridge

Hi,

I've run into a problem with perf on an Intel Sandybridge machine: The LLC-* events never seem to trigger.

For example:

$ perf stat -e LLC-load-misses ls /
[...]
                 0 LLC-load-misses

       0.001082639 seconds time elapsed

Non-LLC events work fine:

$ perf stat -e cache-misses ls /
[...]
             4,272 cache-misses

       0.002945606 seconds time elapsed

This is on a Intel i5 machine (i5-2520M), running a fully updated Fedora 16 ('perf --version': 3.3.2-6.fc16.x86_64, 'uname -r':
3.3.2-6.fc16.x86_64).

Any ideas?

David

Quoted 3 lines · David Wragg

I've run into a problem with perf on an Intel Sandybridge machine: The LLC-* events never seem to trigger.
[...]

I have a same problem on my i7-3930K machine. I guess it's because of lacking of extra register (MSP_OFFCORE_RSP_X) settings. But I have no idea of how I can set it properly :(.

Quoted 5 lines · Namhyung Kim

Quoted 3 lines · David Wragg

I've run into a problem with perf on an Intel Sandybridge machine: The LLC-* events never seem to trigger.
[...]

Quoted 3 lines

I have a same problem on my i7-3930K machine. I guess it's because of lacking of extra register (MSP_OFFCORE_RSP_X) settings. But I have no idea of how I can set it properly :(.

Ok, I've done some further digging around, and it doesn't look like the patch "perf events, x86: Implement Sandybridge last-level cache events" at <https://lkml.org/lkml/2011/5/9/80> ever got merged. It's not clear why.

Quoted 5 lines · David Wragg

Ok, I've done some further digging around, and it doesn't look like the patch "perf events, x86: Implement Sandybridge last-level cache events" at <https://lkml.org/lkml/2011/5/9/80> ever got merged. It's not clear why.

It seems that PeterZ and Ingo don't want an unverified patch get merged. But you can still test with it and, hopefully, provide us a verification :).