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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2011-03-31 05:35:24 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-03-31 15:02:55 +0400 |
| commit | 800cd25c12981c99e5401c3551ffffd99f1c6c85 (patch) | |
| tree | 8a3b1ef662a9190219aaaad842072495fcd70654 /tools/perf | |
| parent | 20443384fe090c5f8aeb016e7e85659c5bbdd69f (diff) | |
| download | linux-800cd25c12981c99e5401c3551ffffd99f1c6c85.tar.xz | |
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>
Diffstat (limited to 'tools/perf')
| -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 db6adecf46f1..17d1dcb3c667 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -41,7 +41,7 @@ static u64 user_interval = ULLONG_MAX; static u64 default_interval = 0; static unsigned int page_size; -static unsigned int mmap_pages = 128; +static unsigned int mmap_pages = UINT_MAX; static unsigned int user_freq = UINT_MAX; static int freq = 1000; static int output; @@ -513,6 +513,10 @@ static int __cmd_record(int argc, const char **argv) if (have_tracepoints(&evsel_list->entries)) perf_header__set_feat(&session->header, HEADER_TRACE_INFO); + /* 512 kiB: default amount of unprivileged mlocked memory */ + if (mmap_pages == UINT_MAX) + mmap_pages = (512 * 1024) / page_size; + if (forks) { child_pid = fork(); if (child_pid < 0) { |