diff options
author | Frederic Weisbecker <fweisbec@gmail.com> | 2011-03-30 21:35:24 -0400 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2011-03-31 07:02:55 -0400 |
commit | 800cd25c12981c99e5401c3551ffffd99f1c6c85 (patch) | |
tree | 8a3b1ef662a9190219aaaad842072495fcd70654 | |
parent | 20443384fe090c5f8aeb016e7e85659c5bbdd69f (diff) |
perf: mmap 512 kiB by default
The default setting of perf record is to mmap 128 pages if the user
did not override with -m.
However the page size may vary accross different architecture
settings, giving different default size between each.
Moreover the kernel side still has a default max number of mlocked
pages of 512 kiB + 1 page for unprivileged users. 128 + 1 pages
with page size > 4096 overlaps this threshold.
Thus, better adapt to this limitation and set the default number of
pages to fit those 512 kiB + 1 page.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <1301535324-9735-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r-- | tools/perf/builtin-record.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index db6adecf46f..17d1dcb3c66 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c | |||
@@ -41,7 +41,7 @@ static u64 user_interval = ULLONG_MAX; | |||
41 | static u64 default_interval = 0; | 41 | static u64 default_interval = 0; |
42 | 42 | ||
43 | static unsigned int page_size; | 43 | static unsigned int page_size; |
44 | static unsigned int mmap_pages = 128; | 44 | static unsigned int mmap_pages = UINT_MAX; |
45 | static unsigned int user_freq = UINT_MAX; | 45 | static unsigned int user_freq = UINT_MAX; |
46 | static int freq = 1000; | 46 | static int freq = 1000; |
47 | static int output; | 47 | static int output; |
@@ -513,6 +513,10 @@ static int __cmd_record(int argc, const char **argv) | |||
513 | if (have_tracepoints(&evsel_list->entries)) | 513 | if (have_tracepoints(&evsel_list->entries)) |
514 | perf_header__set_feat(&session->header, HEADER_TRACE_INFO); | 514 | perf_header__set_feat(&session->header, HEADER_TRACE_INFO); |
515 | 515 | ||
516 | /* 512 kiB: default amount of unprivileged mlocked memory */ | ||
517 | if (mmap_pages == UINT_MAX) | ||
518 | mmap_pages = (512 * 1024) / page_size; | ||
519 | |||
516 | if (forks) { | 520 | if (forks) { |
517 | child_pid = fork(); | 521 | child_pid = fork(); |
518 | if (child_pid < 0) { | 522 | if (child_pid < 0) { |