]> git.ipfire.org Git - thirdparty/linux.git/commitdiff
perf lock: Fix parse_lock_type which only retrieve one lock flag
authorChun-Tse Shao <ctshao@google.com>
Thu, 16 Jan 2025 23:58:14 +0000 (15:58 -0800)
committerNamhyung Kim <namhyung@kernel.org>
Fri, 17 Jan 2025 18:11:57 +0000 (10:11 -0800)
`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: 9.313 [sec]

         9.313976 usecs/op
           107365 ops/sec
   contended   total wait     max wait     avg wait         type   caller

         176      1.65 ms     19.43 us      9.38 us        mutex   pipe_read+0x57
          34    180.14 us     10.93 us      5.30 us        mutex   pipe_write+0x50
           7     77.48 us     16.09 us     11.07 us        mutex   do_epoll_wait+0x24d
           7     74.70 us     13.50 us     10.67 us        mutex   do_epoll_wait+0x24d
           3     35.97 us     14.44 us     11.99 us     rwlock:W   ep_done_scan+0x2d
           3     35.00 us     12.23 us     11.66 us     rwlock:W   do_epoll_wait+0x255
           2     15.88 us     11.96 us      7.94 us     rwlock:W   do_epoll_wait+0x47c
           1     15.23 us     15.23 us     15.23 us     rwlock:W   do_epoll_wait+0x4d0
           1     14.26 us     14.26 us     14.26 us     rwlock:W   ep_done_scan+0x2d
           2     14.00 us      7.99 us      7.00 us        mutex   pipe_read+0x282
           1     12.29 us     12.29 us     12.29 us     rwlock:R   ep_poll_callback+0x35
           1     12.02 us     12.02 us     12.02 us     rwlock:W   do_epoll_ctl+0xb65
           1     10.25 us     10.25 us     10.25 us     rwlock:R   ep_poll_callback+0x35
           1      7.86 us      7.86 us      7.86 us        mutex   do_epoll_ctl+0x6c1
           1      5.04 us      5.04 us      5.04 us        mutex   do_epoll_ctl+0x3d4

[namhyung: Add a comment and rename to 'mutex:spin' for consistency

Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Cc: nick.forrington@arm.com
Link: https://lore.kernel.org/r/20250116235838.2769691-1-ctshao@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
tools/perf/builtin-lock.c

index 94a2bc15a2fa718732d5f2c937bf9054a4e3fa45..70440966d8e3d3ae47d8c721c4851cbec612da47 100644 (file)
@@ -1484,8 +1484,8 @@ 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" },
+       /* alias for optimistic spinning only */
+       { LCB_F_MUTEX | LCB_F_SPIN,     "mutex:spin",   "mutex-spin" },
 };
 
 static const char *get_type_str(unsigned int flags)
@@ -1510,19 +1510,6 @@ static const char *get_type_name(unsigned int flags)
        return "unknown";
 }
 
-static unsigned int get_type_flag(const char *str)
-{
-       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))
-                       return lock_type_table[i].flags;
-       }
-       return UINT_MAX;
-}
-
 static void lock_filter_finish(void)
 {
        zfree(&filters.types);
@@ -2254,29 +2241,58 @@ static int parse_lock_type(const struct option *opt __maybe_unused, const char *
                           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);
+               bool found = false;
 
-               if (flags == -1U) {
-                       pr_err("Unknown lock flags: %s\n", tok);
-                       ret = -1;
-                       break;
+               /* `tok` is `str` in `lock_type_table` if it contains ':'. */
+               if (strchr(tok, ':')) {
+                       for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
+                               if (!strcmp(lock_type_table[i].str, tok) &&
+                                   add_lock_type(lock_type_table[i].flags)) {
+                                       found = true;
+                                       break;
+                               }
+                       }
+
+                       if (!found) {
+                               pr_err("Unknown lock flags name: %s\n", tok);
+                               free(s);
+                               return -1;
+                       }
+
+                       continue;
                }
 
-               if (!add_lock_type(flags)) {
-                       ret = -1;
-                       break;
+               /*
+                * Otherwise `tok` is `name` in `lock_type_table`.
+                * Single lock name could contain multiple flags.
+                */
+               for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
+                       if (!strcmp(lock_type_table[i].name, tok)) {
+                               if (add_lock_type(lock_type_table[i].flags)) {
+                                       found = true;
+                               } else {
+                                       free(s);
+                                       return -1;
+                               }
+                       }
                }
+
+               if (!found) {
+                       pr_err("Unknown lock name: %s\n", tok);
+                       free(s);
+                       return -1;
+               }
+
        }
 
        free(s);
-       return ret;
+       return 0;
 }
 
 static bool add_lock_addr(unsigned long addr)