PEBS (in perf) stopped working from 3.6 -> 3.7

[Steinar H. Gunderson]

[Please Cc me on any replies; I'm not subscribed to lkml]

Hi,

I recently upgraded from 3.6.5 to 3.7.1 to get around some MM issues that
have been bothering me. However, it appears it broke PEBS:

  pannekake:/usr/src/linux-3.7.1# perf record -a -e cycles:pp

  Error: sys_perf_event_open() syscall returned with 95 (Operation not supported).  /bin/dmesg may provide additional information.

  Fatal: No hardware sampling interrupt available. No APIC? If so then you can boot the kernel with the "lapic" boot parameter to force-enable it.

Non-precise tracing works fine. This used to work in 3.6.5, and I used make
oldconfig (not that I can find any .config settings that would seem relevant
either). I certainly have APIC. There's nothing in dmesg about the error.
I'm using perf built from the same kernel tree (ie., 3.7.1).

This is on a dual Xeon E5520 (ie. Westmere), on a Supermicro board.

/* Steinar */
-- 
Chief, Tech:Server
http://www.sesse.net/
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