aboutsummaryrefslogtreecommitdiffstats
path: root/tools
diff options
context:
space:
mode:
authorFrederic Weisbecker <fweisbec@gmail.com>2011-03-31 03:35:24 +0200
committerIngo Molnar <mingo@elte.hu>2011-03-31 13:02:55 +0200
commit800cd25c12981c99e5401c3551ffffd99f1c6c85 (patch)
tree8a3b1ef662a9190219aaaad842072495fcd70654 /tools
parent20443384fe090c5f8aeb016e7e85659c5bbdd69f (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>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/builtin-record.c6
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) {

Privacy Policy