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Message-ID: <20241122002752.4179915-1-ctshao@google.com>
Date: Fri, 22 Nov 2024 00:27:51 +0000
From: Chun-Tse Shao <ctshao@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: Chun-Tse Shao <ctshao@...gle.com>, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>
Subject: [PATCH v2] perf lock: Fix parse_lock_type which only retrieve one
lock flag
`parse_lock_type` can only add the first lock flag in `lock_type_table`
given input `str`. For example, for `Y rwlock`, it only adds `rwlock:R`
into this perf session. Another example is for `-Y mutex`, it only adds
the mutex without `LCB_F_SPIN` flag. The patch fixes this issue, makes
sure both `rwlock:R` and `rwlock:W` will be added with `-Y rwlock`, and
so on.
Testing:
$ ./perf lock con -ab -Y mutex,rwlock -- perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
Total time: 8.425 [sec]
8.425402 usecs/op
118688 ops/sec
contended total wait max wait avg wait type caller
194 1.68 ms 44.16 us 8.66 us mutex pipe_read+0x57
10 423.03 us 44.27 us 42.30 us rwlock:W do_exit+0x365
54 254.67 us 58.87 us 4.72 us mutex pipe_write+0x50
21 146.64 us 11.54 us 6.98 us mutex pipe_read+0x282
10 141.27 us 20.62 us 14.13 us rwlock:W release_task+0x6f
5 58.92 us 16.37 us 11.78 us mutex do_epoll_wait+0x24d
3 29.81 us 17.66 us 9.94 us mutex do_epoll_ctl+0x6c1
4 26.82 us 11.02 us 6.70 us mutex do_epoll_wait+0x24d
2 18.32 us 12.49 us 9.16 us rwlock:W do_epoll_wait+0x255
1 11.34 us 11.34 us 11.34 us rwlock:W ep_done_scan+0x2d
1 11.02 us 11.02 us 11.02 us rwlock:R mm_update_next_owner+0x4e
1 10.60 us 10.60 us 10.60 us rwlock:W do_epoll_ctl+0xb65
1 9.90 us 9.90 us 9.90 us rwlock:W do_exit+0x365
Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
Signed-off-by: Chun-Tse Shao <ctshao@...gle.com>
---
tools/perf/builtin-lock.c | 93 ++++++++++++++++++++++++++-------------
1 file changed, 62 insertions(+), 31 deletions(-)
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 062e2b56a2ab..052dbf423efd 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -15,6 +15,7 @@
#include "util/lock-contention.h"
#include "util/bpf_skel/lock_data.h"
+#include <string.h>
#include <subcmd/pager.h>
#include <subcmd/parse-options.h>
#include "util/trace-event.h"
@@ -1575,8 +1576,13 @@ static void sort_result(void)
static const struct {
unsigned int flags;
- const char *str;
+ /* Name of the lock. */
const char *name;
+ /*
+ * Name of the group this lock belongs to.
+ * For example, both rwlock:R and rwlock:W belong to rwlock.
+ */
+ const char *group;
} lock_type_table[] = {
{ 0, "semaphore", "semaphore" },
{ LCB_F_SPIN, "spinlock", "spinlock" },
@@ -1591,42 +1597,38 @@ static const struct {
{ LCB_F_PERCPU | LCB_F_WRITE, "pcpu-sem:W", "percpu-rwsem" },
{ LCB_F_MUTEX, "mutex", "mutex" },
{ LCB_F_MUTEX | LCB_F_SPIN, "mutex", "mutex" },
- /* alias for get_type_flag() */
- { LCB_F_MUTEX | LCB_F_SPIN, "mutex-spin", "mutex" },
};
-static const char *get_type_str(unsigned int flags)
+static const char *get_type_name(unsigned int flags)
{
flags &= LCB_F_MAX_FLAGS - 1;
for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
if (lock_type_table[i].flags == flags)
- return lock_type_table[i].str;
+ return lock_type_table[i].name;
}
return "unknown";
}
-static const char *get_type_name(unsigned int flags)
+static const char *get_type_group(unsigned int flags)
{
flags &= LCB_F_MAX_FLAGS - 1;
for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
if (lock_type_table[i].flags == flags)
- return lock_type_table[i].name;
+ return lock_type_table[i].group;
}
return "unknown";
}
-static unsigned int get_type_flag(const char *str)
+static unsigned int get_type_flags_by_name(const char *name)
{
for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
- if (!strcmp(lock_type_table[i].name, str))
- return lock_type_table[i].flags;
- }
- for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
- if (!strcmp(lock_type_table[i].str, str))
+ if (!strcmp(lock_type_table[i].name, name))
return lock_type_table[i].flags;
}
+
+ pr_err("Unknown lock flags: %s\n", name);
return UINT_MAX;
}
@@ -1732,7 +1734,8 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
switch (aggr_mode) {
case LOCK_AGGR_CALLER:
- fprintf(lock_output, " %10s %s\n", get_type_str(st->flags), st->name);
+ fprintf(lock_output, " %10s %s\n",
+ get_type_name(st->flags), st->name);
break;
case LOCK_AGGR_TASK:
pid = st->addr;
@@ -1742,7 +1745,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
break;
case LOCK_AGGR_ADDR:
fprintf(lock_output, " %016llx %s (%s)\n", (unsigned long long)st->addr,
- st->name, get_type_name(st->flags));
+ st->name, get_type_group(st->flags));
break;
case LOCK_AGGR_CGROUP:
fprintf(lock_output, " %s\n", st->name);
@@ -1783,7 +1786,8 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
switch (aggr_mode) {
case LOCK_AGGR_CALLER:
- fprintf(lock_output, "%s%s %s", get_type_str(st->flags), sep, st->name);
+ fprintf(lock_output, "%s%s %s",
+ get_type_name(st->flags), sep, st->name);
if (verbose <= 0)
fprintf(lock_output, "\n");
break;
@@ -1795,7 +1799,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
break;
case LOCK_AGGR_ADDR:
fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
- st->name, sep, get_type_name(st->flags));
+ st->name, sep, get_type_group(st->flags));
break;
case LOCK_AGGR_CGROUP:
fprintf(lock_output, "%s\n",st->name);
@@ -2338,41 +2342,68 @@ static bool add_lock_type(unsigned int flags)
unsigned int *tmp;
tmp = realloc(filters.types, (filters.nr_types + 1) * sizeof(*filters.types));
- if (tmp == NULL)
+ if (tmp == NULL) {
+ pr_err("Failed to add lock flags: %u\n", flags);
return false;
+ }
tmp[filters.nr_types++] = flags;
filters.types = tmp;
return true;
}
-static int parse_lock_type(const struct option *opt __maybe_unused, const char *str,
- int unset __maybe_unused)
+static int parse_lock_type(const struct option *opt __maybe_unused,
+ const char *str, int unset __maybe_unused)
{
char *s, *tmp, *tok;
- int ret = 0;
s = strdup(str);
if (s == NULL)
return -1;
- for (tok = strtok_r(s, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
- unsigned int flags = get_type_flag(tok);
+ for (tok = strtok_r(s, ", ", &tmp); tok;
+ tok = strtok_r(NULL, ", ", &tmp)) {
+ bool found = false;
- if (flags == -1U) {
- pr_err("Unknown lock flags: %s\n", tok);
- ret = -1;
- break;
+ /* `tok` is a lock name if it contains ':'. */
+ if (strchr(tok, ':')) {
+ unsigned int flags = get_type_flags_by_name(tok);
+
+ if (flags == UINT_MAX || !add_lock_type(flags)) {
+ free(s);
+ return -1;
+ }
+ continue;
}
- if (!add_lock_type(flags)) {
- ret = -1;
- break;
+ /* Otherwise look up flags by lock group */
+ /*
+ * By documentation, `percpu-rwmem` should be `pcpu-sem`.
+ * For backward compatibility, we replace pcpu-sem with percpu-rwmem.
+ */
+ if (!strcmp(tok, "pcpu-sem"))
+ tok = (char *)"percpu-rwsem";
+
+ for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
+ if (!strcmp(lock_type_table[i].group, tok)) {
+ if (add_lock_type(lock_type_table[i].flags)) {
+ found = true;
+ } else {
+ free(s);
+ return -1;
+ }
+ }
+ }
+
+ if (!found) {
+ pr_err("Unknown lock flags: %s\n", tok);
+ free(s);
+ return -1;
}
}
free(s);
- return ret;
+ return 0;
}
static bool add_lock_addr(unsigned long addr)
--
2.47.0.371.ga323438b13-goog
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