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Message-Id: <20211129231830.1117781-6-namhyung@kernel.org>
Date: Mon, 29 Nov 2021 15:18:30 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...hat.com>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>,
Andi Kleen <ak@...ux.intel.com>,
Ian Rogers <irogers@...gle.com>,
Stephane Eranian <eranian@...gle.com>,
Song Liu <songliubraving@...com>,
Changbin Du <changbin.du@...il.com>
Subject: [PATCH 5/5] perf ftrace: Implement cpu and task filters in BPF
Honor cpu and task options to set up filters (by pid or tid) in the
BPF program. For example, the following command will show latency of
the mutex_lock for process 2570.
# perf ftrace latency -b -T mutex_lock -p 2570 sleep 3
# DURATION | COUNT | GRAPH |
0 - 1 us | 675 | ############################## |
1 - 2 us | 9 | |
2 - 4 us | 0 | |
4 - 8 us | 0 | |
8 - 16 us | 0 | |
16 - 32 us | 0 | |
32 - 64 us | 0 | |
64 - 128 us | 0 | |
128 - 256 us | 0 | |
256 - 512 us | 0 | |
512 - 1024 us | 0 | |
1 - 2 ms | 0 | |
2 - 4 ms | 0 | |
4 - 8 ms | 0 | |
8 - 16 ms | 0 | |
16 - 32 ms | 0 | |
32 - 64 ms | 0 | |
64 - 128 ms | 0 | |
128 - 256 ms | 0 | |
256 - 512 ms | 0 | |
512 - 1024 ms | 0 | |
1 - ... s | 0 | |
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/util/bpf_ftrace.c | 41 +++++++++++++++++++++
tools/perf/util/bpf_skel/func_latency.bpf.c | 21 +++++++++++
2 files changed, 62 insertions(+)
diff --git a/tools/perf/util/bpf_ftrace.c b/tools/perf/util/bpf_ftrace.c
index 1975a6fe73c9..18d6f1558163 100644
--- a/tools/perf/util/bpf_ftrace.c
+++ b/tools/perf/util/bpf_ftrace.c
@@ -6,7 +6,10 @@
#include <linux/err.h>
#include "util/ftrace.h"
+#include "util/cpumap.h"
+#include "util/thread_map.h"
#include "util/debug.h"
+#include "util/evlist.h"
#include "util/bpf_counter.h"
#include "util/bpf_skel/func_latency.skel.h"
@@ -16,6 +19,7 @@ static struct func_latency_bpf *skel;
int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
{
int fd, err;
+ int i, ncpus = 1, ntasks = 1;
struct filter_entry *func;
struct bpf_link *begin_link, *end_link;
@@ -33,6 +37,17 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
return -1;
}
+ /* don't need to set cpu filter for system-wide mode */
+ if (ftrace->target.cpu_list) {
+ ncpus = perf_cpu_map__nr(ftrace->evlist->core.cpus);
+ bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
+ }
+
+ if (target__has_task(&ftrace->target) || target__none(&ftrace->target)) {
+ ntasks = perf_thread_map__nr(ftrace->evlist->core.threads);
+ bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
+ }
+
set_max_rlimit();
err = func_latency_bpf__load(skel);
@@ -41,6 +56,32 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
goto out;
}
+ if (ftrace->target.cpu_list) {
+ u32 cpu;
+ u8 val = 1;
+
+ skel->bss->has_cpu = 1;
+ fd = bpf_map__fd(skel->maps.cpu_filter);
+
+ for (i = 0; i < ncpus; i++) {
+ cpu = cpu_map__cpu(ftrace->evlist->core.cpus, i);
+ bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
+ }
+ }
+
+ if (target__has_task(&ftrace->target) || target__none(&ftrace->target)) {
+ u32 pid;
+ u8 val = 1;
+
+ skel->bss->has_task = 1;
+ fd = bpf_map__fd(skel->maps.task_filter);
+
+ for (i = 0; i < ntasks; i++) {
+ pid = perf_thread_map__pid(ftrace->evlist->core.threads, i);
+ bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
+ }
+ }
+
begin_link = bpf_program__attach_kprobe(skel->progs.func_begin,
false, func->name);
if (IS_ERR(begin_link)) {
diff --git a/tools/perf/util/bpf_skel/func_latency.bpf.c b/tools/perf/util/bpf_skel/func_latency.bpf.c
index d7d31cfeabf8..17a2a53b4f16 100644
--- a/tools/perf/util/bpf_skel/func_latency.bpf.c
+++ b/tools/perf/util/bpf_skel/func_latency.bpf.c
@@ -36,6 +36,8 @@ struct {
int enabled = 0;
+int has_cpu = 0;
+int has_task = 0;
SEC("kprobe/func")
int BPF_PROG(func_begin)
@@ -46,6 +48,25 @@ int BPF_PROG(func_begin)
return 0;
key = bpf_get_current_pid_tgid();
+
+ if (has_cpu) {
+ __u32 cpu = bpf_get_smp_processor_id();
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&cpu_filter, &cpu);
+ if (!ok)
+ return 0;
+ }
+
+ if (has_task) {
+ __u32 pid = key & 0xffffffff;
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&task_filter, &pid);
+ if (!ok)
+ return 0;
+ }
+
now = bpf_ktime_get_ns();
// overwrite timestamp for nested functions
--
2.34.0.rc2.393.gf8c9666880-goog
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