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| author | Mike Frysinger <vapier@gentoo.org> | 2009-06-12 13:17:43 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-12 19:37:30 +0200 |
| commit | 018df72dd01576ab199c6129233cdeaf1409958b (patch) | |
| tree | 1561017056cc1289e373b094d72ba41a4382308b | |
| parent | 974802eaa1afdc87e00821df7020a2b3c6fee623 (diff) | |
| download | linux-018df72dd01576ab199c6129233cdeaf1409958b.tar.bz2 | |
perf_counter: Start documenting HAVE_PERF_COUNTERS requirements
Help out arch porters who want to support perf counters by listing some
basic requirements.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1244827063-24046-1-git-send-email-vapier@gentoo.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | init/Kconfig | 2 | ||||
| -rw-r--r-- | tools/perf/design.txt | 15 |
2 files changed, 17 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index c649657e2259..d3a50967c337 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -936,6 +936,8 @@ config AIO config HAVE_PERF_COUNTERS bool + help + See tools/perf/design.txt for details. menu "Performance Counters" diff --git a/tools/perf/design.txt b/tools/perf/design.txt index 860e116d979c..f71e0d245cba 100644 --- a/tools/perf/design.txt +++ b/tools/perf/design.txt @@ -440,3 +440,18 @@ by this process or by another, and doesn't affect any counters that this process has created on other processes. It only enables or disables the group leaders, not any other members in the groups. + +Arch requirements +----------------- + +If your architecture does not have hardware performance metrics, you can +still use the generic software counters based on hrtimers for sampling. + +So to start with, in order to add HAVE_PERF_COUNTERS to your Kconfig, you +will need at least this: + - asm/perf_counter.h - a basic stub will suffice at first + - support for atomic64 types (and associated helper functions) + - set_perf_counter_pending() implemented + +If your architecture does have hardware capabilities, you can override the +weak stub hw_perf_counter_init() to register hardware counters. |