This covers two different use cases. The first one is cgroup
filtering given by -G/--cgroup option which controls the off-cpu
profiling for tasks in the given cgroups only.
The other use case is cgroup sampling which is enabled by
--all-cgroups option and it adds PERF_SAMPLE_CGROUP to the sample_type
to set the cgroup id of the task in the sample data.
Example output.
$ sudo perf record -a --off-cpu --all-cgroups sleep 1
$ sudo perf report --stdio -s comm,cgroup --call-graph=no
...
# Samples: 144 of event 'offcpu-time'
# Event count (approx.):
48452045427
#
# Children Self Command Cgroup
# ........ ........ ............... ..........................................
#
61.57% 5.60% Chrome_ChildIOT /user.slice/user-657345.slice/user@657345.service/app.slice/...
29.51% 7.38% Web Content /user.slice/user-657345.slice/user@657345.service/app.slice/...
17.48% 1.59% Chrome_IOThread /user.slice/user-657345.slice/user@657345.service/app.slice/...
16.48% 4.12% pipewire-pulse /user.slice/user-657345.slice/user@657345.service/session.slice/...
14.48% 2.07% perf /user.slice/user-657345.slice/user@657345.service/app.slice/...
14.30% 7.15% CompositorTileW /user.slice/user-657345.slice/user@657345.service/app.slice/...
13.33% 6.67% Timer /user.slice/user-657345.slice/user@657345.service/app.slice/...
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220518224725.742882-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
static int record__config_off_cpu(struct record *rec)
{
- return off_cpu_prepare(rec->evlist, &rec->opts.target);
+ return off_cpu_prepare(rec->evlist, &rec->opts.target, &rec->opts);
}
static bool record__kcore_readable(struct machine *machine)
#include "util/evlist.h"
#include "util/off_cpu.h"
#include "util/perf-hooks.h"
+#include "util/record.h"
#include "util/session.h"
#include "util/target.h"
#include "util/cpumap.h"
#include "util/thread_map.h"
+#include "util/cgroup.h"
#include <bpf/bpf.h>
#include "bpf_skel/off_cpu.skel.h"
u32 tgid;
u32 stack_id;
u32 state;
+ u64 cgroup_id;
};
union off_cpu_data {
}
}
-int off_cpu_prepare(struct evlist *evlist, struct target *target)
+int off_cpu_prepare(struct evlist *evlist, struct target *target,
+ struct record_opts *opts)
{
int err, fd, i;
- int ncpus = 1, ntasks = 1;
+ int ncpus = 1, ntasks = 1, ncgrps = 1;
if (off_cpu_config(evlist) < 0) {
pr_err("Failed to config off-cpu BPF event\n");
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
}
+ if (evlist__first(evlist)->cgrp) {
+ ncgrps = evlist->core.nr_entries - 1; /* excluding a dummy */
+ bpf_map__set_max_entries(skel->maps.cgroup_filter, ncgrps);
+
+ if (!cgroup_is_v2("perf_event"))
+ skel->rodata->uses_cgroup_v1 = true;
+ }
+
+ if (opts->record_cgroup) {
+ skel->rodata->needs_cgroup = true;
+
+ if (!cgroup_is_v2("perf_event"))
+ skel->rodata->uses_cgroup_v1 = true;
+ }
+
set_max_rlimit();
check_sched_switch_args();
}
}
+ if (evlist__first(evlist)->cgrp) {
+ struct evsel *evsel;
+ u8 val = 1;
+
+ skel->bss->has_cgroup = 1;
+ fd = bpf_map__fd(skel->maps.cgroup_filter);
+
+ evlist__for_each_entry(evlist, evsel) {
+ struct cgroup *cgrp = evsel->cgrp;
+
+ if (cgrp == NULL)
+ continue;
+
+ if (!cgrp->id && read_cgroup_id(cgrp) < 0) {
+ pr_err("Failed to read cgroup id of %s\n",
+ cgrp->name);
+ goto out;
+ }
+
+ bpf_map_update_elem(fd, &cgrp->id, &val, BPF_ANY);
+ }
+ }
+
err = off_cpu_bpf__attach(skel);
if (err) {
pr_err("Failed to attach off-cpu BPF skeleton\n");
/* calculate sample callchain data array length */
n += len + 2;
}
+ if (sample_type & PERF_SAMPLE_CGROUP)
+ data.array[n++] = key.cgroup_id;
/* TODO: handle more sample types */
size = n * sizeof(u64);
__u32 tgid;
__u32 stack_id;
__u32 state;
+ __u64 cgroup_id;
};
struct {
__uint(max_entries, 1);
} task_filter SEC(".maps");
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(key_size, sizeof(__u64));
+ __uint(value_size, sizeof(__u8));
+ __uint(max_entries, 1);
+} cgroup_filter SEC(".maps");
+
/* old kernel task_struct definition */
struct task_struct___old {
long state;
int enabled = 0;
int has_cpu = 0;
int has_task = 0;
+int has_cgroup = 0;
const volatile bool has_prev_state = false;
+const volatile bool needs_cgroup = false;
+const volatile bool uses_cgroup_v1 = false;
/*
* Old kernel used to call it task_struct->state and now it's '__state'.
return BPF_CORE_READ(t_old, state);
}
+static inline __u64 get_cgroup_id(struct task_struct *t)
+{
+ struct cgroup *cgrp;
+
+ if (uses_cgroup_v1)
+ cgrp = BPF_CORE_READ(t, cgroups, subsys[perf_event_cgrp_id], cgroup);
+ else
+ cgrp = BPF_CORE_READ(t, cgroups, dfl_cgrp);
+
+ return BPF_CORE_READ(cgrp, kn, id);
+}
+
static inline int can_record(struct task_struct *t, int state)
{
/* kernel threads don't have user stack */
return 0;
}
+ if (has_cgroup) {
+ __u8 *ok;
+ __u64 cgrp_id = get_cgroup_id(t);
+
+ ok = bpf_map_lookup_elem(&cgroup_filter, &cgrp_id);
+ if (!ok)
+ return 0;
+ }
+
return 1;
}
.tgid = next->tgid,
.stack_id = pelem->stack_id,
.state = pelem->state,
+ .cgroup_id = needs_cgroup ? get_cgroup_id(next) : 0,
};
__u64 delta = ts - pelem->timestamp;
__u64 *total;
struct evlist;
struct target;
struct perf_session;
+struct record_opts;
#define OFFCPU_EVENT "offcpu-time"
#ifdef HAVE_BPF_SKEL
-int off_cpu_prepare(struct evlist *evlist, struct target *target);
+int off_cpu_prepare(struct evlist *evlist, struct target *target,
+ struct record_opts *opts);
int off_cpu_write(struct perf_session *session);
#else
static inline int off_cpu_prepare(struct evlist *evlist __maybe_unused,
- struct target *target __maybe_unused)
+ struct target *target __maybe_unused,
+ struct record_opts *opts __maybe_unused)
{
return -1;
}