linux-kernel - [PATCH v1] perf stat bperf cgroup: Increase MAX

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Message-ID: <20251016150718.2778187-1-irogers@google.com>
Date: Thu, 16 Oct 2025 08:07:18 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	bpf@...r.kernel.org
Subject: [PATCH v1] perf stat bperf cgroup: Increase MAX_EVENTS from 32 to 1024

The MAX_EVENTS value ensured a counted loop presumably to satisfy the
BPF verifier. It is possible to go past 32 events when gathering
uncore events. Increase the amount to 1024 as that should provide some
amount of headroom.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/bpf_skel/bperf_cgroup.bpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
index 57cab7647a9a..18ab4d9b49ff 100644
--- a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
+++ b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
@@ -7,7 +7,7 @@
 #include <bpf/bpf_core_read.h>
 
 #define MAX_LEVELS  10  // max cgroup hierarchy level: arbitrary
-#define MAX_EVENTS  32  // max events per cgroup: arbitrary
+#define MAX_EVENTS  1024  // max events per cgroup: arbitrary
 
 // NOTE: many of map and global data will be modified before loading
 //       from the userspace (perf tool) using the skeleton helpers.
-- 
2.51.0.788.g6d19910ace-goog