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Message-ID: <20251001181229.1010340-2-irogers@google.com>
Date: Wed, 1 Oct 2025 11:12:28 -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>,
Tengda Wu <wutengda@...weicloud.com>, Gabriele Monaco <gmonaco@...hat.com>,
James Clark <james.clark@...aro.org>, Howard Chu <howardchu95@...il.com>,
Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, Song Liu <songliubraving@...com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH v1 2/2] perf bpf_counter: Fix handling of cpumap fixing hybrid
Don't open evsels on all CPUs, open them just on the CPUs they
support. This avoids opening say an e-core event on a p-core and
getting a failure - achieve this by getting rid of the "all_cpu_map".
In install_pe functions don't use the cpu_map_idx as a CPU number,
translate the cpu_map_idx, which is a dense index into the cpu_map
skipping holes at the beginning, to a proper CPU number.
Before:
```
$ perf stat --bpf-counters -a -e cycles,instructions -- sleep 1
Performance counter stats for 'system wide':
<not supported> cpu_atom/cycles/
566,270,672 cpu_core/cycles/
<not supported> cpu_atom/instructions/
572,792,836 cpu_core/instructions/ # 1.01 insn per cycle
1.001595384 seconds time elapsed
```
After:
```
$ perf stat --bpf-counters -a -e cycles,instructions -- sleep 1
Performance counter stats for 'system wide':
443,299,201 cpu_atom/cycles/
1,233,919,737 cpu_core/cycles/
213,634,112 cpu_atom/instructions/ # 0.48 insn per cycle
2,758,965,527 cpu_core/instructions/ # 2.24 insn per cycle
1.001699485 seconds time elapsed
```
Fixes: 7fac83aaf2ee ("perf stat: Introduce 'bperf' to share hardware PMCs with BPF")
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
tools/perf/util/bpf_counter.c | 26 ++++++++++----------------
tools/perf/util/bpf_counter_cgroup.c | 3 ++-
2 files changed, 12 insertions(+), 17 deletions(-)
diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
index 1c6cb5ea077e..ca5d01b9017d 100644
--- a/tools/perf/util/bpf_counter.c
+++ b/tools/perf/util/bpf_counter.c
@@ -336,6 +336,7 @@ static int bpf_program_profiler__install_pe(struct evsel *evsel, int cpu_map_idx
{
struct bpf_prog_profiler_bpf *skel;
struct bpf_counter *counter;
+ int cpu = perf_cpu_map__cpu(evsel->core.cpus, cpu_map_idx).cpu;
int ret;
list_for_each_entry(counter, &evsel->bpf_counter_list, list) {
@@ -343,7 +344,7 @@ static int bpf_program_profiler__install_pe(struct evsel *evsel, int cpu_map_idx
assert(skel != NULL);
ret = bpf_map_update_elem(bpf_map__fd(skel->maps.events),
- &cpu_map_idx, &fd, BPF_ANY);
+ &cpu, &fd, BPF_ANY);
if (ret)
return ret;
}
@@ -451,7 +452,6 @@ static int bperf_check_target(struct evsel *evsel,
return 0;
}
-static struct perf_cpu_map *all_cpu_map;
static __u32 filter_entry_cnt;
static int bperf_reload_leader_program(struct evsel *evsel, int attr_map_fd,
@@ -495,7 +495,7 @@ static int bperf_reload_leader_program(struct evsel *evsel, int attr_map_fd,
* following evsel__open_per_cpu call
*/
evsel->leader_skel = skel;
- evsel__open_per_cpu(evsel, all_cpu_map, -1);
+ evsel__open(evsel, evsel->core.cpus, evsel->core.threads);
out:
bperf_leader_bpf__destroy(skel);
@@ -533,12 +533,6 @@ static int bperf__load(struct evsel *evsel, struct target *target)
if (bperf_check_target(evsel, target, &filter_type, &filter_entry_cnt))
return -1;
- if (!all_cpu_map) {
- all_cpu_map = perf_cpu_map__new_online_cpus();
- if (!all_cpu_map)
- return -1;
- }
-
evsel->bperf_leader_prog_fd = -1;
evsel->bperf_leader_link_fd = -1;
@@ -656,9 +650,10 @@ static int bperf__load(struct evsel *evsel, struct target *target)
static int bperf__install_pe(struct evsel *evsel, int cpu_map_idx, int fd)
{
struct bperf_leader_bpf *skel = evsel->leader_skel;
+ int cpu = perf_cpu_map__cpu(evsel->core.cpus, cpu_map_idx).cpu;
return bpf_map_update_elem(bpf_map__fd(skel->maps.events),
- &cpu_map_idx, &fd, BPF_ANY);
+ &cpu, &fd, BPF_ANY);
}
/*
@@ -667,13 +662,12 @@ static int bperf__install_pe(struct evsel *evsel, int cpu_map_idx, int fd)
*/
static int bperf_sync_counters(struct evsel *evsel)
{
- int num_cpu, i, cpu;
+ struct perf_cpu cpu;
+ int idx;
+
+ perf_cpu_map__for_each_cpu(cpu, idx, evsel->core.cpus)
+ bperf_trigger_reading(evsel->bperf_leader_prog_fd, cpu.cpu);
- num_cpu = perf_cpu_map__nr(all_cpu_map);
- for (i = 0; i < num_cpu; i++) {
- cpu = perf_cpu_map__cpu(all_cpu_map, i).cpu;
- bperf_trigger_reading(evsel->bperf_leader_prog_fd, cpu);
- }
return 0;
}
diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
index ed6a29b106b4..690be3ce3e11 100644
--- a/tools/perf/util/bpf_counter_cgroup.c
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -186,7 +186,8 @@ static int bperf_cgrp__load(struct evsel *evsel,
}
static int bperf_cgrp__install_pe(struct evsel *evsel __maybe_unused,
- int cpu __maybe_unused, int fd __maybe_unused)
+ int cpu_map_idx __maybe_unused,
+ int fd __maybe_unused)
{
/* nothing to do */
return 0;
--
2.51.0.618.g983fd99d29-goog
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