diff options
| author | Beau Belgrave <beaub@linux.microsoft.com> | 2022-07-28 16:33:08 -0700 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-09-29 10:17:37 -0400 |
| commit | 39d6d08b2edf99c4b39a689a70bf0adee065b357 (patch) | |
| tree | 2dfb47d9ea7e51415af2cd79815f2c9597786655 /tools/testing/selftests/user_events/perf_test.c | |
| parent | d401b72458562c2f2a81dad162de5c1b8e191e17 (diff) | |
tracing/user_events: Use bits vs bytes for enabled status page data
User processes may require many events and when they do the cache
performance of a byte index status check is less ideal than a bit index.
The previous event limit per-page was 4096, the new limit is 32,768.
This change adds a bitwise index to the user_reg struct. Programs check
that the bit at status_bit has a bit set within the status page(s).
Link: https://lkml.kernel.org/r/20220728233309.1896-6-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'tools/testing/selftests/user_events/perf_test.c')
| -rw-r--r-- | tools/testing/selftests/user_events/perf_test.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/tools/testing/selftests/user_events/perf_test.c b/tools/testing/selftests/user_events/perf_test.c index 26851d51d6bb..8b4c7879d5a7 100644 --- a/tools/testing/selftests/user_events/perf_test.c +++ b/tools/testing/selftests/user_events/perf_test.c @@ -35,6 +35,11 @@ static long perf_event_open(struct perf_event_attr *pe, pid_t pid, return syscall(__NR_perf_event_open, pe, pid, cpu, group_fd, flags); } +static inline int status_check(char *status_page, int status_bit) +{ + return status_page[status_bit >> 3] & (1 << (status_bit & 7)); +} + static int get_id(void) { FILE *fp = fopen(id_file, "r"); @@ -120,8 +125,8 @@ TEST_F(user, perf_write) { /* Register should work */ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, ®)); ASSERT_EQ(0, reg.write_index); - ASSERT_NE(0, reg.status_index); - ASSERT_EQ(0, status_page[reg.status_index]); + ASSERT_NE(0, reg.status_bit); + ASSERT_EQ(0, status_check(status_page, reg.status_bit)); /* Id should be there */ id = get_id(); @@ -144,7 +149,7 @@ TEST_F(user, perf_write) { ASSERT_NE(MAP_FAILED, perf_page); /* Status should be updated */ - ASSERT_EQ(EVENT_STATUS_PERF, status_page[reg.status_index]); + ASSERT_NE(0, status_check(status_page, reg.status_bit)); event.index = reg.write_index; event.field1 = 0xc001; |