Thread (84 messages) 84 messages, 6 authors, 2022-01-12

Re: [PATCH v4 48/48] perf cpumap: Give CPUs their own type.

From: Ian Rogers <irogers@google.com>
Date: 2022-01-11 19:17:23
Also in: linux-perf-users, lkml

On Mon, Jan 10, 2022 at 11:50 AM Arnaldo Carvalho de Melo
[off-list ref] wrote:
Em Tue, Jan 04, 2022 at 10:13:51PM -0800, Ian Rogers escreveu:
quoted
A common problem is confusing CPU map indices with the CPU, by wrapping
the CPU with a struct then this is avoided. This approach is similar to
atomic_t.
This one needed this to build with BUILD_BPF_SKEL=1, please check, I'll
soon push this to tmp.perf/perf_cpu so that you can take a look and test
it.

Thanks Arnaldo, I did eye-ball one issue where cpu_map__default_new's
behavior would be impacted (nr would be 1 rather than nr_cpus). The
fix is:
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -18,7 +18,7 @@ static struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus)
        if (!cpus)
                return NULL;

-       cpus->nr = 1;
+       cpus->nr = nr_cpus;
        refcount_set(&cpus->refcnt, 1);
        return cpus;
 }
Could you add that into this patch as well?

Thanks,
Ian

quoted hunk ↗ jump to hunk
- Arnaldo
diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
index 80d1a3a31052fe55..328479df5e16a638 100644
--- a/tools/perf/util/bpf_counter.c
+++ b/tools/perf/util/bpf_counter.c
@@ -540,7 +540,7 @@ static int bperf__load(struct evsel *evsel, struct target *target)
                    filter_type == BPERF_FILTER_TGID)
                        key = evsel->core.threads->map[i].pid;
                else if (filter_type == BPERF_FILTER_CPU)
-                       key = evsel->core.cpus->map[i];
+                       key = evsel->core.cpus->map[i].cpu;
                else
                        break;
@@ -584,7 +584,7 @@ static int bperf_sync_counters(struct evsel *evsel)

        num_cpu = all_cpu_map->nr;
        for (i = 0; i < num_cpu; i++) {
-               cpu = all_cpu_map->map[i];
+               cpu = all_cpu_map->map[i].cpu;
                bperf_trigger_reading(evsel->bperf_leader_prog_fd, cpu);
        }
        return 0;
@@ -605,7 +605,7 @@ static int bperf__disable(struct evsel *evsel)
 static int bperf__read(struct evsel *evsel)
 {
        struct bperf_follower_bpf *skel = evsel->follower_skel;
-       __u32 num_cpu_bpf = cpu__max_cpu();
+       __u32 num_cpu_bpf = cpu__max_cpu().cpu;
        struct bpf_perf_event_value values[num_cpu_bpf];
        int reading_map_fd, err = 0;
        __u32 i;
@@ -615,6 +615,7 @@ static int bperf__read(struct evsel *evsel)
        reading_map_fd = bpf_map__fd(skel->maps.accum_readings);

        for (i = 0; i < bpf_map__max_entries(skel->maps.accum_readings); i++) {
+               struct perf_cpu entry;
                __u32 cpu;

                err = bpf_map_lookup_elem(reading_map_fd, &i, values);
@@ -624,14 +625,15 @@ static int bperf__read(struct evsel *evsel)
                case BPERF_FILTER_GLOBAL:
                        assert(i == 0);

-                       perf_cpu_map__for_each_cpu(cpu, j, all_cpu_map) {
+                       perf_cpu_map__for_each_cpu(entry, j, all_cpu_map) {
+                               cpu = entry.cpu;
                                perf_counts(evsel->counts, cpu, 0)->val = values[cpu].counter;
                                perf_counts(evsel->counts, cpu, 0)->ena = values[cpu].enabled;
                                perf_counts(evsel->counts, cpu, 0)->run = values[cpu].running;
                        }
                        break;
                case BPERF_FILTER_CPU:
-                       cpu = evsel->core.cpus->map[i];
+                       cpu = evsel->core.cpus->map[i].cpu;
                        perf_counts(evsel->counts, i, 0)->val = values[cpu].counter;
                        perf_counts(evsel->counts, i, 0)->ena = values[cpu].enabled;
                        perf_counts(evsel->counts, i, 0)->run = values[cpu].running;
diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
index cbc6c2bca488f6bf..631e34a0b66ff084 100644
--- a/tools/perf/util/bpf_counter_cgroup.c
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -48,7 +48,7 @@ static int bperf_load_program(struct evlist *evlist)
        struct cgroup *cgrp, *leader_cgrp;
        __u32 i, cpu;
        __u32 nr_cpus = evlist->core.all_cpus->nr;
-       int total_cpus = cpu__max_cpu();
+       int total_cpus = cpu__max_cpu().cpu;
        int map_size, map_fd;
        int prog_fd, err;
@@ -125,7 +125,7 @@ static int bperf_load_program(struct evlist *evlist)
                        for (cpu = 0; cpu < nr_cpus; cpu++) {
                                int fd = FD(evsel, cpu);
                                __u32 idx = evsel->core.idx * total_cpus +
-                                       evlist->core.all_cpus->map[cpu];
+                                       evlist->core.all_cpus->map[cpu].cpu;

                                err = bpf_map_update_elem(map_fd, &idx, &fd,
                                                          BPF_ANY);
@@ -212,7 +212,7 @@ static int bperf_cgrp__sync_counters(struct evlist *evlist)
        int prog_fd = bpf_program__fd(skel->progs.trigger_read);

        for (i = 0; i < nr_cpus; i++) {
-               cpu = evlist->core.all_cpus->map[i];
+               cpu = evlist->core.all_cpus->map[i].cpu;
                bperf_trigger_reading(prog_fd, cpu);
        }
@@ -245,7 +245,7 @@ static int bperf_cgrp__read(struct evsel *evsel)
 {
        struct evlist *evlist = evsel->evlist;
        int i, cpu, nr_cpus = evlist->core.all_cpus->nr;
-       int total_cpus = cpu__max_cpu();
+       int total_cpus = cpu__max_cpu().cpu;
        struct perf_counts_values *counts;
        struct bpf_perf_event_value *values;
        int reading_map_fd, err = 0;
@@ -272,7 +272,7 @@ static int bperf_cgrp__read(struct evsel *evsel)
                }

                for (i = 0; i < nr_cpus; i++) {
-                       cpu = evlist->core.all_cpus->map[i];
+                       cpu = evlist->core.all_cpus->map[i].cpu;

                        counts = perf_counts(evsel->counts, i, 0);
                        counts->val = values[cpu].counter;
diff --git a/tools/perf/util/bpf_ftrace.c b/tools/perf/util/bpf_ftrace.c
index 28dc4c60c7884818..d756cc66eef32ae8 100644
--- a/tools/perf/util/bpf_ftrace.c
+++ b/tools/perf/util/bpf_ftrace.c
@@ -63,7 +63,7 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
                fd = bpf_map__fd(skel->maps.cpu_filter);

                for (i = 0; i < ncpus; i++) {
-                       cpu = perf_cpu_map__cpu(ftrace->evlist->core.cpus, i);
+                       cpu = perf_cpu_map__cpu(ftrace->evlist->core.cpus, i).cpu;
                        bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
                }
        }
@@ -122,7 +122,7 @@ int perf_ftrace__latency_read_bpf(struct perf_ftrace *ftrace __maybe_unused,
        int i, fd, err;
        u32 idx;
        u64 *hist;
-       int ncpus = cpu__max_cpu();
+       int ncpus = cpu__max_cpu().cpu;

        fd = bpf_map__fd(skel->maps.latency);
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