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perf evlist: Round mmap pages to power 2 - v2

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Currently perf requires the -m / --mmap_pages option to be a power of 2.

To be more user friendly perf should automatically round this up to the
next power of 2.

Currently:
  $ perf record -m 3 -a -- sleep 1
  --mmap_pages/-m value must be a power of two.sleep: Terminated

With patch:
  $ perf record -m 3 -a -- sleep 1
  rounding mmap pages size to 16384 (4 pages)
  ...

v2: Add bytes units to rounding message per Ingo's request. Other
    suggestions (e.g., prefixing INFO) should be addressed by wrapping
    pr_info to catch all instances.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1384267617-3446-3-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
David Ahern 2013-11-12 07:46:54 -07:00 committed by Arnaldo Carvalho de Melo
parent 8973504be7
commit 9639837e95
1 changed files with 6 additions and 12 deletions
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18
tools/perf/util/evlist.c
View file

@ -710,7 +710,6 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
{
unsigned int *mmap_pages = opt->value;
unsigned long pages, val;
size_t size;
static struct parse_tag tags[] = {
{ .tag = 'B', .mult = 1 },
{ .tag = 'K', .mult = 1 << 10 },
@ -726,11 +725,6 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
if (val != (unsigned long) -1) {
/* we got file size value */
pages = PERF_ALIGN(val, page_size) / page_size;
if (pages < (1UL << 31) && !is_power_of_2(pages)) {
pages = next_pow2(pages);
pr_info("rounding mmap pages size to %lu (%lu pages)\n",
pages * page_size, pages);
}
} else {
/* we got pages count value */
char *eptr;
@ -741,14 +735,14 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
}
}
if (pages > UINT_MAX || pages > SIZE_MAX / page_size) {
pr_err("--mmap_pages/-m value too big\n");
return -1;
if (pages < (1UL << 31) && !is_power_of_2(pages)) {
pages = next_pow2(pages);
pr_info("rounding mmap pages size to %lu bytes (%lu pages)\n",
pages * page_size, pages);
}
size = perf_evlist__mmap_size(pages);
if (!size) {
pr_err("--mmap_pages/-m value must be a power of two.");
if (pages > UINT_MAX || pages > SIZE_MAX / page_size) {
pr_err("--mmap_pages/-m value too big\n");
return -1;
}