Em Sun, Oct 04, 2015 at 01:48:21PM +0200, Milian Wolff escreveu:
> Hey all,
>
> would it be possible to add a feature to perf to only grab callgraphs for a
> certain selection of events? E.g. thinking about a lock contention profile of
> a Qt application, I'd listen to
>
> -e syscalls:sys_enter_futex,syscalls:sys_exit_futex
>
> Now, with the dwarf unwinder this easily produces huge data files in the
> order
> of gigabytes. This cost could easily be reduced by a factor of two, as one
> only needs the callgraphs for syscalls:sys_enter_futex - the TID should be
> enough to find the callgraph for the enter event from the exit trace point.
>
> Could someone guide me in implementing such a feature to make it possible to
> filter the events which trigger the collection of a callgraph? Or is that
> already possible somehow?
Can you please check if this suits you, it is already in the tree:
commit e637d17757a10732fa5d573c18f20b3cd4d31245
Author: He Kuang <heku...@huawei.com>
Date: Mon Sep 28 03:52:16 2015 +0000
perf tools: Enable event_config terms to tracepoint events
This patch enables config terms for tracepoint perf events. Valid terms
for tracepoint events are 'call-graph' and 'stack-size', so we can use
different callgraph settings for each event and eliminate unnecessary
overhead.
Here is an example for using different call-graph config for each
tracepoint.
$ perf record -e syscalls:sys_enter_write/call-graph=fp/
-e syscalls:sys_exit_write/call-graph=no/
dd if=/dev/zero of=test bs=4k count=10
$ perf report --stdio
#
# Total Lost Samples: 0
#
# Samples: 13 of event 'syscalls:sys_enter_write'
# Event count (approx.): 13
#
# Children Self Command Shared Object Symbol
# ........ ........ ....... .................. ......................
#
76.92% 76.92% dd libpthread-2.20.so [.] __write_nocancel
|
---__write_nocancel
23.08% 23.08% dd libc-2.20.so [.] write
|
---write
|
|--33.33%-- 0x2031342820736574
|
|--33.33%-- 0xa6e69207364726f
|
--33.33%-- 0x34202c7320393039
...
# Samples: 13 of event 'syscalls:sys_exit_write'
# Event count (approx.): 13
#
# Children Self Command Shared Object Symbol
# ........ ........ ....... .................. ......................
#
76.92% 76.92% dd libpthread-2.20.so [.] __write_nocancel
23.08% 23.08% dd libc-2.20.so [.] write
7.69% 0.00% dd [unknown] [.] 0x0a6e69207364726f
7.69% 0.00% dd [unknown] [.] 0x2031342820736574
7.69% 0.00% dd [unknown] [.] 0x34202c7320393039
Signed-off-by: He Kuang <heku...@huawei.com>
Acked-by: Jiri Olsa <jo...@kernel.org>
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Kan Liang <kan.li...@intel.com>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Wang Nan <wangn...@huawei.com>
Cc: pi3or...@163.com
Link:
http://lkml.kernel.org/r/1443412336-120050-4-git-send-email-heku...@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
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