XPost: linux.kernel, linux.debian.kernel
Hello,
On Tue, May 06, 2025 at 09:02:20PM +0200, Salvatore Bonaccorso wrote:
Hi,
Pasi Kallinen reported in Debian a regression with perf r5101c4
counter, initially it was found in https://github.com/rr-debugger/rr/issues/3949 but said to be a kernel problem.
What's the '51' part? I don't think it's defined.
$ grep . -r /sys/bus/event_source/devices/cpu/format/
/sys/bus/event_source/devices/cpu/format/event:config:0-7
/sys/bus/event_source/devices/cpu/format/pc:config:19
/sys/bus/event_source/devices/cpu/format/edge:config:18
/sys/bus/event_source/devices/cpu/format/offcore_rsp:config1:0-63
/sys/bus/event_source/devices/cpu/format/ldlat:config1:0-15
/sys/bus/event_source/devices/cpu/format/inv:config:23
/sys/bus/event_source/devices/cpu/format/umask:config:8-15
/sys/bus/event_source/devices/cpu/format/frontend:config1:0-23
/sys/bus/event_source/devices/cpu/format/cmask:config:24-31
Nothing for bit 16, 20 and 22 on the 'config' field.
Is it possible to fix rr to use a correct event encoding instead?
Thanks,
Namhyung
On Tue, May 06, 2025 at 07:18:39PM +0300, Pasi Kallinen wrote:
Package: src:linux
Version: 6.12.25-1
Severity: normal
X-Debbugs-Cc: debian-amd64@lists.debian.org, paxed@alt.org
User: debian-amd64@lists.debian.org
Usertags: amd64
Dear Maintainer,
perf stat -e r5101c4 true
reports "not supported".
The counters worked in kernel 6.11.10.
I first noticed this not working when updating to 6.12.22.
Booting back to 6.11.10, the counters work correctly.
Does this ring a bell?
Would you be able to bisect the changes to identify where the
behaviour changed?
Regards,
Salvatore
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