]> www.infradead.org Git - users/jedix/linux-maple.git/commit
perf x86/topdown: Fix topdown leader sampling test error on hybrid
authorDapeng Mi <dapeng1.mi@linux.intel.com>
Fri, 7 Mar 2025 02:39:03 +0000 (18:39 -0800)
committerNamhyung Kim <namhyung@kernel.org>
Wed, 12 Mar 2025 02:00:50 +0000 (19:00 -0700)
commitb74683b3bb224eccb644cf260753dfc82e802d92
tree8c3c067fcb763d9a9c8053b09396f2e360843ea2
parentfd5de637a4e9a4cfe987962f0a74f8ed84fca78e
perf x86/topdown: Fix topdown leader sampling test error on hybrid

When running topdown leader smapling test on Intel hybrid platforms,
such as LNL/ARL, we see the below error.

Topdown leader sampling test
Topdown leader sampling [Failed topdown events not reordered correctly]

It indciates the below command fails.

perf record -o "${perfdata}" -e "{instructions,slots,topdown-retiring}:S" true

The root cause is that perf tool creats a perf event for each PMU type
if it can create.

As for this command, there would be 5 perf events created,
cpu_atom/instructions/,cpu_atom/topdown_retiring/,
cpu_core/slots/,cpu_core/instructions/,cpu_core/topdown-retiring/

For these 5 events, the 2 cpu_atom events are in a group and the other 3
cpu_core events are in another group.

When arch_topdown_sample_read() traverses all these 5 events, events
cpu_atom/instructions/ and cpu_core/slots/ don't have a same group
leade, and then return false directly and lead to cpu_core/slots/ event
is used to sample and this is not allowed by PMU driver.

It's a overkill to return false directly if "evsel->core.leader !=
 leader->core.leader" since there could be multiple groups in the event
list.

Just "continue" instead of "return false" to fix this issue.

Fixes: 1e53e9d1787b ("perf x86/topdown: Correct leader selection with sample_read enabled")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Tested-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250307023906.1135613-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
tools/perf/arch/x86/util/topdown.c