Hi Greg,
On Sat, 22 Jun 2013 23:17:20 -0400, Greg Price wrote:
> For example, in an application with an expensive function
> implemented with deeply nested recursive calls, the default
> call-graph presentation is dominated by the different callchains
> within that function. By treating the function as a black box,
> we can collect the callchains leading into the function and
> compactly identify what to blame for expensive calls.
>
> For example, in this report the callers of garbage_collect() are
s/callers/callees/ ?
And it'd be better it shows more lines after garbage_collect so that one
can see its callers also to understand what it does more clearly.
> scattered across the tree:
> $ perf report -d ruby 2>- | grep -m10 ^[^#]*[a-z]
> 22.03% ruby [.] gc_mark
> --- gc_mark
> |--59.40%-- mark_keyvalue
> | st_foreach
> | gc_mark_children
> | |--99.75%-- rb_gc_mark
> | | rb_vm_mark
> | | gc_mark_children
> | | gc_marks
> | | |--99.00%-- garbage_collect
>
> If we make garbage_collect() a black box, its callers are coalesced:
Again, s/callers/callees/ ?
> $ perf report --blackbox garbage_collect -d ruby 2>- | grep -m10 ^[^#]*[a-z]
> 72.92% ruby [.] garbage_collect
> --- garbage_collect
> vm_xmalloc
> |--47.08%-- ruby_xmalloc
> | st_insert2
> | rb_hash_aset
> | |--98.45%-- features_index_add
> | | rb_provide_feature
> | | rb_require_safe
> | | vm_call_method
>
> Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
> Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
> Cc: Paul Mackerras <pau...@samba.org>
> Cc: Ingo Molnar <mi...@redhat.com>
> Cc: Jiri Olsa <jo...@redhat.com>
> Cc: David Ahern <dsah...@gmail.com>
> Signed-off-by: Greg Price <pr...@mit.edu>
> ---
>
> On Fri, Jan 11, 2013 at 02:27:36AM -0300, Arnaldo Carvalho de Melo wrote:
>> Looks like an interesting feature, will review this soon,
>
> Rebased on top of v3.10-rc7, please take a look at your convenience.
>
>
> tools/perf/builtin-report.c | 19 ++++++++++++++++---
> tools/perf/builtin-top.c | 3 +--
> tools/perf/util/machine.c | 26 +++++++++++++++++---------
> tools/perf/util/machine.h | 9 ++++++++-
> tools/perf/util/session.c | 3 +--
You need to update the doc too.
> 5 files changed, 43 insertions(+), 17 deletions(-)
[SNIP]
> @@ -1211,8 +1214,13 @@ static int machine__resolve_callchain_sample(struct
> machine *machine,
> MAP__FUNCTION, ip, &al, NULL);
> if (al.sym != NULL) {
> if (sort__has_parent && !*parent &&
> - symbol__match_parent_regex(al.sym))
> + symbol__match_regex(al.sym, &parent_regex))
> *parent = al.sym;
> + else if (have_blackbox && root_al &&
> + symbol__match_regex(al.sym, &blackbox_regex)) {
> + *root_al = al;
> + callchain_cursor_reset(&callchain_cursor);
Okay, this is where the magic happens. :)
So it overwrites the original 'al' in process_sample_event() to
blackboxed symbol and drop the callchain. Wouldn't it deserve a
comment? :)
> + }
> if (!symbol_conf.use_callchain)
> break;
pp
This is unrelated to this patch, but why is this line needed? I guess
this check should be done before calling this function.
Thanks,
Namhyung
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