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path: root/tools/perf/util/bpf_off_cpu.c
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Diffstat (limited to 'tools/perf/util/bpf_off_cpu.c')
-rw-r--r--tools/perf/util/bpf_off_cpu.c140
1 files changed, 86 insertions, 54 deletions
diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
index 6af36142dc5a..c367fefe6ecb 100644
--- a/tools/perf/util/bpf_off_cpu.c
+++ b/tools/perf/util/bpf_off_cpu.c
@@ -13,6 +13,8 @@
#include "util/cgroup.h"
#include "util/strlist.h"
#include <bpf/bpf.h>
+#include <internal/xyarray.h>
+#include <linux/time64.h>
#include "bpf_skel/off_cpu.skel.h"
@@ -36,34 +38,25 @@ union off_cpu_data {
u64 array[1024 / sizeof(u64)];
};
+u64 off_cpu_raw[MAX_STACKS + 5];
+
static int off_cpu_config(struct evlist *evlist)
{
+ char off_cpu_event[64];
struct evsel *evsel;
- struct perf_event_attr attr = {
- .type = PERF_TYPE_SOFTWARE,
- .config = PERF_COUNT_SW_BPF_OUTPUT,
- .size = sizeof(attr), /* to capture ABI version */
- };
- char *evname = strdup(OFFCPU_EVENT);
- if (evname == NULL)
- return -ENOMEM;
-
- evsel = evsel__new(&attr);
- if (!evsel) {
- free(evname);
- return -ENOMEM;
+ scnprintf(off_cpu_event, sizeof(off_cpu_event), "bpf-output/name=%s/", OFFCPU_EVENT);
+ if (parse_event(evlist, off_cpu_event)) {
+ pr_err("Failed to open off-cpu event\n");
+ return -1;
}
- evsel->core.attr.freq = 1;
- evsel->core.attr.sample_period = 1;
- /* off-cpu analysis depends on stack trace */
- evsel->core.attr.sample_type = PERF_SAMPLE_CALLCHAIN;
-
- evlist__add(evlist, evsel);
-
- free(evsel->name);
- evsel->name = evname;
+ evlist__for_each_entry(evlist, evsel) {
+ if (evsel__is_offcpu_event(evsel)) {
+ evsel->core.system_wide = true;
+ break;
+ }
+ }
return 0;
}
@@ -71,21 +64,42 @@ static int off_cpu_config(struct evlist *evlist)
static void off_cpu_start(void *arg)
{
struct evlist *evlist = arg;
+ struct evsel *evsel;
+ struct perf_cpu pcpu;
+ int i;
/* update task filter for the given workload */
- if (!skel->bss->has_cpu && !skel->bss->has_task &&
+ if (skel->rodata->has_task && skel->rodata->uses_tgid &&
perf_thread_map__pid(evlist->core.threads, 0) != -1) {
int fd;
u32 pid;
u8 val = 1;
- skel->bss->has_task = 1;
- skel->bss->uses_tgid = 1;
fd = bpf_map__fd(skel->maps.task_filter);
pid = perf_thread_map__pid(evlist->core.threads, 0);
bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
}
+ /* update BPF perf_event map */
+ evsel = evlist__find_evsel_by_str(evlist, OFFCPU_EVENT);
+ if (evsel == NULL) {
+ pr_err("%s evsel not found\n", OFFCPU_EVENT);
+ return;
+ }
+
+ perf_cpu_map__for_each_cpu(pcpu, i, evsel->core.cpus) {
+ int err;
+ int cpu_nr = pcpu.cpu;
+
+ err = bpf_map__update_elem(skel->maps.offcpu_output, &cpu_nr, sizeof(int),
+ xyarray__entry(evsel->core.fd, cpu_nr, 0),
+ sizeof(int), BPF_ANY);
+ if (err) {
+ pr_err("Failed to update perf event map for direct off-cpu dumping\n");
+ return;
+ }
+ }
+
skel->bss->enabled = 1;
}
@@ -102,6 +116,11 @@ static void check_sched_switch_args(void)
const struct btf_type *t1, *t2, *t3;
u32 type_id;
+ if (!btf) {
+ pr_debug("Missing btf, check if CONFIG_DEBUG_INFO_BTF is enabled\n");
+ goto cleanup;
+ }
+
type_id = btf__find_by_name_kind(btf, "btf_trace_sched_switch",
BTF_KIND_TYPEDEF);
if ((s32)type_id < 0)
@@ -148,6 +167,7 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
if (target->cpu_list) {
ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
+ skel->rodata->has_cpu = 1;
}
if (target->pid) {
@@ -173,11 +193,16 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
ntasks = MAX_PROC;
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
+ skel->rodata->has_task = 1;
+ skel->rodata->uses_tgid = 1;
} else if (target__has_task(target)) {
ntasks = perf_thread_map__nr(evlist->core.threads);
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
+ skel->rodata->has_task = 1;
} else if (target__none(target)) {
bpf_map__set_max_entries(skel->maps.task_filter, MAX_PROC);
+ skel->rodata->has_task = 1;
+ skel->rodata->uses_tgid = 1;
}
if (evlist__first(evlist)->cgrp) {
@@ -186,6 +211,7 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
if (!cgroup_is_v2("perf_event"))
skel->rodata->uses_cgroup_v1 = true;
+ skel->rodata->has_cgroup = 1;
}
if (opts->record_cgroup) {
@@ -208,7 +234,6 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
u32 cpu;
u8 val = 1;
- skel->bss->has_cpu = 1;
fd = bpf_map__fd(skel->maps.cpu_filter);
for (i = 0; i < ncpus; i++) {
@@ -220,8 +245,6 @@ int off_cpu_prepare(struct evlist *evlist, struct target *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) {
@@ -240,7 +263,6 @@ int off_cpu_prepare(struct evlist *evlist, struct target *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++) {
@@ -253,7 +275,6 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
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) {
@@ -272,6 +293,8 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target,
}
}
+ skel->bss->offcpu_thresh_ns = opts->off_cpu_thresh_ns;
+
err = off_cpu_bpf__attach(skel);
if (err) {
pr_err("Failed to attach off-cpu BPF skeleton\n");
@@ -295,6 +318,7 @@ int off_cpu_write(struct perf_session *session)
{
int bytes = 0, size;
int fd, stack;
+ u32 raw_size;
u64 sample_type, val, sid = 0;
struct evsel *evsel;
struct perf_data_file *file = &session->data->file;
@@ -334,46 +358,54 @@ int off_cpu_write(struct perf_session *session)
while (!bpf_map_get_next_key(fd, &prev, &key)) {
int n = 1; /* start from perf_event_header */
- int ip_pos = -1;
bpf_map_lookup_elem(fd, &key, &val);
+ /* zero-fill some of the fields, will be overwritten by raw_data when parsing */
if (sample_type & PERF_SAMPLE_IDENTIFIER)
data.array[n++] = sid;
- if (sample_type & PERF_SAMPLE_IP) {
- ip_pos = n;
+ if (sample_type & PERF_SAMPLE_IP)
data.array[n++] = 0; /* will be updated */
- }
if (sample_type & PERF_SAMPLE_TID)
- data.array[n++] = (u64)key.pid << 32 | key.tgid;
+ data.array[n++] = 0;
if (sample_type & PERF_SAMPLE_TIME)
data.array[n++] = tstamp;
- if (sample_type & PERF_SAMPLE_ID)
- data.array[n++] = sid;
if (sample_type & PERF_SAMPLE_CPU)
data.array[n++] = 0;
if (sample_type & PERF_SAMPLE_PERIOD)
- data.array[n++] = val;
- if (sample_type & PERF_SAMPLE_CALLCHAIN) {
- int len = 0;
-
- /* data.array[n] is callchain->nr (updated later) */
- data.array[n + 1] = PERF_CONTEXT_USER;
- data.array[n + 2] = 0;
-
- bpf_map_lookup_elem(stack, &key.stack_id, &data.array[n + 2]);
- while (data.array[n + 2 + len])
+ data.array[n++] = 0;
+ if (sample_type & PERF_SAMPLE_RAW) {
+ /*
+ * [ size ][ data ]
+ * [ data ]
+ * [ data ]
+ * [ data ]
+ * [ data ][ empty]
+ */
+ int len = 0, i = 0;
+ void *raw_data = (void *)data.array + n * sizeof(u64);
+
+ off_cpu_raw[i++] = (u64)key.pid << 32 | key.tgid;
+ off_cpu_raw[i++] = val;
+
+ /* off_cpu_raw[i] is callchain->nr (updated later) */
+ off_cpu_raw[i + 1] = PERF_CONTEXT_USER;
+ off_cpu_raw[i + 2] = 0;
+
+ bpf_map_lookup_elem(stack, &key.stack_id, &off_cpu_raw[i + 2]);
+ while (off_cpu_raw[i + 2 + len])
len++;
- /* update length of callchain */
- data.array[n] = len + 1;
+ off_cpu_raw[i] = len + 1;
+ i += len + 2;
+
+ off_cpu_raw[i++] = key.cgroup_id;
- /* update sample ip with the first callchain entry */
- if (ip_pos >= 0)
- data.array[ip_pos] = data.array[n + 2];
+ raw_size = i * sizeof(u64) + sizeof(u32); /* 4 bytes for alignment */
+ memcpy(raw_data, &raw_size, sizeof(raw_size));
+ memcpy(raw_data + sizeof(u32), off_cpu_raw, i * sizeof(u64));
- /* calculate sample callchain data array length */
- n += len + 2;
+ n += i + 1;
}
if (sample_type & PERF_SAMPLE_CGROUP)
data.array[n++] = key.cgroup_id;
generated by cgit (git 2.34.1) at 2025-07-25 17:46:02 +0000