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perf offcpu: Parse process id separately

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The current target code uses thread id for tracking tasks because
perf_events need to be opened for each task.  But we can use tgid in
BPF maps and check it easily.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@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/20220811185456.194721-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2022-08-11 11:54:54 -07:00 committed by Arnaldo Carvalho de Melo
parent 07fc958b0c
commit d6f415ca33
1 changed files with 43 additions and 2 deletions
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45
tools/perf/util/bpf_off_cpu.c
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@ -11,6 +11,7 @@
#include "util/cpumap.h"
#include "util/thread_map.h"
#include "util/cgroup.h"
#include "util/strlist.h"
#include <bpf/bpf.h>
#include "bpf_skel/off_cpu.skel.h"
@ -125,6 +126,8 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
{
int err, fd, i;
int ncpus = 1, ntasks = 1, ncgrps = 1;
struct strlist *pid_slist = NULL;
struct str_node *pos;
if (off_cpu_config(evlist) < 0) {
pr_err("Failed to config off-cpu BPF event\n");
@ -143,7 +146,26 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
}
if (target__has_task(target)) {
if (target->pid) {
pid_slist = strlist__new(target->pid, NULL);
if (!pid_slist) {
pr_err("Failed to create a strlist for pid\n");
return -1;
}
ntasks = 0;
strlist__for_each_entry(pos, pid_slist) {
char *end_ptr;
int pid = strtol(pos->s, &end_ptr, 10);
if (pid == INT_MIN || pid == INT_MAX ||
(*end_ptr != '\0' && *end_ptr != ','))
continue;
ntasks++;
}
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
} else if (target__has_task(target)) {
ntasks = perf_thread_map__nr(evlist->core.threads);
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
}
@ -185,7 +207,26 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
}
}
if (target__has_task(target)) {
if (target->pid) {
u8 val = 1;
skel->bss->has_task = 1;
skel->bss->uses_tgid = 1;
fd = bpf_map__fd(skel->maps.task_filter);
strlist__for_each_entry(pos, pid_slist) {
char *end_ptr;
u32 tgid;
int pid = strtol(pos->s, &end_ptr, 10);
if (pid == INT_MIN || pid == INT_MAX ||
(*end_ptr != '\0' && *end_ptr != ','))
continue;
tgid = pid;
bpf_map_update_elem(fd, &tgid, &val, BPF_ANY);
}
} else if (target__has_task(target)) {
u32 pid;
u8 val = 1;