Commit-ID: 018df72dd01576ab199c6129233cdeaf1409958b Gitweb: http://git.kernel.org/tip/018df72dd01576ab199c6129233cdeaf1409958b Author: Mike Frysinger <vapier@xxxxxxxxxx> AuthorDate: Fri, 12 Jun 2009 13:17:43 -0400 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Fri, 12 Jun 2009 19:37:30 +0200 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@xxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> LKML-Reference: <1244827063-24046-1-git-send-email-vapier@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- init/Kconfig | 2 ++ tools/perf/design.txt | 15 +++++++++++++++ 2 files changed, 17 insertions(+), 0 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index c649657..d3a5096 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 860e116..f71e0d2 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. -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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