[PATCH v9 05/24] perf record: Introduce thread local variable

Alexey Bayduraev
2021-07-02T12:32:59Z

Introduce thread local variable and use it for threaded trace streaming.
Use thread affinity mask instead or record affinity mask in affinity
modes.

Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
tools/perf/builtin-record.c | 139 ++++++++++++++++++++++++------------
1 file changed, 93 insertions(+), 46 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e3752f2559f0..95b6c1c0df44 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -110,6 +110,8 @@ struct record_thread {
unsigned long waking;
};

+static __thread struct record_thread *thread;
+
struct record {
struct perf_tool tool;
struct record_opts opts;
@@ -132,7 +134,6 @@ struct record {
bool timestamp_boundary;
struct switch_output switch_output;
unsigned long long samples;
- struct mmap_cpu_mask affinity_mask;
unsigned long output_max_size; /* = 0: unlimited */
int nr_threads;
struct thread_mask *thread_masks;
@@ -574,7 +575,7 @@ static int record__pushfn(struct mmap *map, void *to, void *bf, size_t size)
bf = map->data;
}

- rec->samples++;
+ thread->samples++;
return record__write(rec, map, bf, size);
}

@@ -1315,19 +1316,29 @@ static struct perf_event_header finished_round_event = {
.type = PERF_RECORD_FINISHED_ROUND,
};

-static void record__adjust_affinity(struct record *rec, struct mmap *map)
+static int record__adjust_affinity(struct record *rec, struct mmap *map)
{
+ int ret = 0;
+
if (rec->opts.affinity != PERF_AFFINITY_SYS &&
- !bitmap_equal(rec->affinity_mask.bits, map->affinity_mask.bits,
- rec->affinity_mask.nbits)) {
- bitmap_zero(rec->affinity_mask.bits, rec->affinity_mask.nbits);
- bitmap_or(rec->affinity_mask.bits, rec->affinity_mask.bits,
- map->affinity_mask.bits, rec->affinity_mask.nbits);
- sched_setaffinity(0, MMAP_CPU_MASK_BYTES(&rec->affinity_mask),
- (cpu_set_t *)rec->affinity_mask.bits);
- if (verbose == 2)
- mmap_cpu_mask__scnprintf(&rec->affinity_mask, "thread");
+ !bitmap_equal(thread->mask->affinity.bits, map->affinity_mask.bits,
+ thread->mask->affinity.nbits)) {
+ bitmap_zero(thread->mask->affinity.bits, thread->mask->affinity.nbits);
+ bitmap_or(thread->mask->affinity.bits, thread->mask->affinity.bits,
+ map->affinity_mask.bits, thread->mask->affinity.nbits);
+ ret = sched_setaffinity(0, MMAP_CPU_MASK_BYTES(&thread->mask->affinity),
+ (cpu_set_t *)thread->mask->affinity.bits);
+ if (ret)
+ pr_err("threads[%d]: sched_setaffinity() call failed: %s\n",
+ thread->tid, strerror(errno));
+ if (verbose == 2) {
+ pr_debug("threads[%d]: addr=", thread->tid);
+ mmap_cpu_mask__scnprintf(&thread->mask->affinity, "thread");
+ pr_debug("threads[%d]: on cpu=%d\n", thread->tid, sched_getcpu());
+ }
}
+
+ return ret;
}

static size_t process_comp_header(void *record, size_t increment)
@@ -1367,14 +1378,17 @@ static int record__mmap_read_evlist(struct record *rec, struct evlist *evlist,
u64 bytes_written = rec->bytes_written;
int i;
int rc = 0;
- struct mmap *maps;
+ int nr_mmaps;
+ struct mmap **maps;
int trace_fd = rec->data.file.fd;
off_t off = 0;

if (!evlist)
return 0;

- maps = overwrite ? evlist->overwrite_mmap : evlist->mmap;
+ nr_mmaps = thread->nr_mmaps;
+ maps = overwrite ? thread->overwrite_maps : thread->maps;
+
if (!maps)
return 0;

@@ -1384,9 +1398,9 @@ static int record__mmap_read_evlist(struct record *rec, struct evlist *evlist,
if (record__aio_enabled(rec))
off = record__aio_get_pos(trace_fd);

- for (i = 0; i < evlist->core.nr_mmaps; i++) {
+ for (i = 0; i < nr_mmaps; i++) {
u64 flush = 0;
- struct mmap *map = &maps[i];
+ struct mmap *map = maps[i];

if (map->core.base) {
record__adjust_affinity(rec, map);
@@ -1449,6 +1463,15 @@ static int record__mmap_read_all(struct record *rec, bool synch)
return record__mmap_read_evlist(rec, rec->evlist, true, synch);
}

+static void record__thread_munmap_filtered(struct fdarray *fda, int fd,
+ void *arg __maybe_unused)
+{
+ struct perf_mmap *map = fda->priv[fd].ptr;
+
+ if (map)
+ perf_mmap__put(map);
+}
+
static void record__init_features(struct record *rec)
{
struct perf_session *session = rec->session;
@@ -1893,6 +1916,33 @@ static void record__uniquify_name(struct record *rec)
}
}

+static int record__start_threads(struct record *rec)
+{
+ struct record_thread *thread_data = rec->thread_data;
+
+ thread = &thread_data[0];
+
+ pr_debug("threads[%d]: started on cpu=%d\n", thread->tid, sched_getcpu());
+
+ return 0;
+}
+
+static int record__stop_threads(struct record *rec, unsigned long *waking)
+{
+ int t;
+ struct record_thread *thread_data = rec->thread_data;
+
+ for (t = 0; t < rec->nr_threads; t++) {
+ rec->samples += thread_data[t].samples;
+ *waking += thread_data[t].waking;
+ pr_debug("threads[%d]: samples=%lld, wakes=%ld, trasferred=%ld, compressed=%ld\n",
+ thread_data[t].tid, thread_data[t].samples, thread_data[t].waking,
+ rec->session->bytes_transferred, rec->session->bytes_compressed);
+ }
+
+ return 0;
+}
+
static int __cmd_record(struct record *rec, int argc, const char **argv)
{
int err;
@@ -2001,7 +2051,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)

if (record__open(rec) != 0) {
err = -1;
- goto out_child;
+ goto out_free_threads;
}
session->header.env.comp_mmap_len = session->evlist->core.mmap_len;

@@ -2009,7 +2059,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
err = record__kcore_copy(&session->machines.host, data);
if (err) {
pr_err("ERROR: Failed to copy kcore\n");
- goto out_child;
+ goto out_free_threads;
}
}

@@ -2020,7 +2070,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
bpf__strerror_apply_obj_config(err, errbuf, sizeof(errbuf));
pr_err("ERROR: Apply config to BPF failed: %s\n",
errbuf);
- goto out_child;
+ goto out_free_threads;
}

/*
@@ -2038,11 +2088,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
if (data->is_pipe) {
err = perf_header__write_pipe(fd);
if (err < 0)
- goto out_child;
+ goto out_free_threads;
} else {
err = perf_session__write_header(session, rec->evlist, fd, false);
if (err < 0)
- goto out_child;
+ goto out_free_threads;
}

err = -1;
@@ -2050,16 +2100,16 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
&& !perf_header__has_feat(&session->header, HEADER_BUILD_ID)) {
pr_err("Couldn't generate buildids. "
"Use --no-buildid to profile anyway.\n");
- goto out_child;
+ goto out_free_threads;
}

err = record__setup_sb_evlist(rec);
if (err)
- goto out_child;
+ goto out_free_threads;

err = record__synthesize(rec, false);
if (err < 0)
- goto out_child;
+ goto out_free_threads;

if (rec->realtime_prio) {
struct sched_param param;
@@ -2068,10 +2118,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
if (sched_setscheduler(0, SCHED_FIFO, &param)) {
pr_err("Could not set realtime priority.\n");
err = -1;
- goto out_child;
+ goto out_free_threads;
}
}

+ if (record__start_threads(rec))
+ goto out_free_threads;
+
/*
* When perf is starting the traced process, all the events
* (apart from group members) have enable_on_exec=1 set,
@@ -2142,7 +2195,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
trigger_ready(&switch_output_trigger);
perf_hooks__invoke_record_start();
for (;;) {
- unsigned long long hits = rec->samples;
+ unsigned long long hits = thread->samples;

/*
* rec->evlist->bkw_mmap_state is possible to be
@@ -2211,20 +2264,24 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
alarm(rec->switch_output.time);
}

- if (hits == rec->samples) {
+ if (hits == thread->samples) {
if (done || draining)
break;
- err = evlist__poll(rec->evlist, -1);
+ err = fdarray__poll(&thread->pollfd, -1);
/*
* Propagate error, only if there's any. Ignore positive
* number of returned events and interrupt error.
*/
if (err > 0 || (err < 0 && errno == EINTR))
err = 0;
- waking++;
+ thread->waking++;

- if (evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
+ if (fdarray__filter(&thread->pollfd, POLLERR | POLLHUP,
+ record__thread_munmap_filtered, NULL) == 0)
draining = true;
+
+ evlist__ctlfd_update(rec->evlist,
+ &thread->pollfd.entries[thread->ctlfd_pos]);
}

if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
@@ -2277,18 +2334,20 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
goto out_child;
}

- if (!quiet)
- fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
-
if (target__none(&rec->opts.target))
record__synthesize_workload(rec, true);

out_child:
- evlist__finalize_ctlfd(rec->evlist);
+ record__stop_threads(rec, &waking);
record__mmap_read_all(rec, true);
+out_free_threads:
record__free_thread_data(rec);
+ evlist__finalize_ctlfd(rec->evlist);
record__aio_mmap_read_sync(rec);

+ if (!quiet)
+ fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
+
if (rec->session->bytes_transferred && rec->session->bytes_compressed) {
ratio = (float)rec->session->bytes_transferred/(float)rec->session->bytes_compressed;
session->header.env.comp_ratio = ratio + 0.5;
@@ -3158,17 +3217,6 @@ int cmd_record(int argc, const char **argv)

symbol__init(NULL);

- if (rec->opts.affinity != PERF_AFFINITY_SYS) {
- rec->affinity_mask.nbits = cpu__max_cpu();
- rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);
- if (!rec->affinity_mask.bits) {
- pr_err("Failed to allocate thread mask for %zd cpus\n", rec->affinity_mask.nbits);
- err = -ENOMEM;
- goto out_opts;
- }
- pr_debug2("thread mask[%zd]: empty\n", rec->affinity_mask.nbits);
- }
-
err = record__auxtrace_init(rec);
if (err)
goto out;
@@ -3306,7 +3354,6 @@ int cmd_record(int argc, const char **argv)

err = __cmd_record(&record, argc, argv);
out:
- bitmap_free(rec->affinity_mask.bits);
evlist__delete(rec->evlist);
symbol__exit();
auxtrace_record__free(rec->itr);
--
2.19.0