perf/amd/ibs: Enable fetch latency filtering

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IBS Fetch on future hardware adds fetch latency filtering which
generates interrupt only when FetchLat value exceeds a programmable
threshold.

Hardware allows threshold in 128-cycle increment (i.e. 128, 256, 384
etc.) from 128 to 1920 cycles. Like the existing IBS filters, samples
that fail the latency test are dropped and IBS restarts internally.

Since hardware supports threshold in multiple of 128, add a software
filter on top to support latency threshold with the granularity of 1
cycle in between [128-1920].

Example:
  # perf record -e ibs_fetch/fetchlat=128/ -c 10000 -a -- sleep 5

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260216042530.1546-5-ravi.bangoria@amd.com

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Ravi Bangoria 2026-02-16 04:25:27 +00:00 • committed by Peter Zijlstra

parent efa5700ec0

commit 35247fa60b

1 changed files with 65 additions and 1 deletions

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arch/x86/events/amd/ibs.c

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