Commit-ID: 9ae5b8790037d05d32746f521af146c32089bfec Gitweb: http://git.kernel.org/tip/9ae5b8790037d05d32746f521af146c32089bfec Author: Steven Rostedt <srostedt@xxxxxxxxxx> AuthorDate: Mon, 20 Apr 2009 10:27:58 -0400 Committer: Steven Rostedt <rostedt@xxxxxxxxxxx> CommitDate: Mon, 20 Apr 2009 11:07:48 -0400 tracing: change branch profiling to a choice selection This patch makes the branch profiling into a choice selection: None - no branch profiling likely/unlikely - only profile likely/unlikely branches all - profile all branches The all profiler will also enable the likely/unlikely branches. This does not change the way the profiler works or the dependencies between the profilers. What this patch does, is keep the branch profiling from being selected by an allyesconfig make. The branch profiler is very intrusive and it is known to break various architecture builds when selected as an allyesconfig. [ Impact: prevent branch profiler from being selected in allyesconfig ] Reported-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Reported-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> --- kernel/trace/Kconfig | 39 +++++++++++++++++++++++++++++++++------ 1 files changed, 33 insertions(+), 6 deletions(-) diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 57981d3..3ee28db 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -212,8 +212,36 @@ config BOOT_TRACER to enable this on bootup. config TRACE_BRANCH_PROFILING - bool "Trace likely/unlikely profiler" + bool select TRACING + +choice + prompt "Branch Profiling" + default BRANCH_PROFILE_NONE + help + The branch profiling is a software profiler. It will add hooks + into the C conditionals to test which path a branch takes. + + The likely/unlikely profiler only looks at the conditions that + are annotated with a likely or unlikely macro. + + The "all branch" profiler will profile every if statement in the + kernel. This profiler will also enable the likely/unlikely + profiler as well. + + Either of the above profilers add a bit of overhead to the system. + If unsure choose "No branch profiling". + +config BRANCH_PROFILE_NONE + bool "No branch profiling" + help + No branch profiling. Branch profiling adds a bit of overhead. + Only enable it if you want to analyse the branching behavior. + Otherwise keep it disabled. + +config PROFILE_ANNOTATED_BRANCHES + bool "Trace likely/unlikely profiler" + select TRACE_BRANCH_PROFILING help This tracer profiles all the the likely and unlikely macros in the kernel. It will display the results in: @@ -223,11 +251,9 @@ config TRACE_BRANCH_PROFILING Note: this will add a significant overhead, only turn this on if you need to profile the system's use of these macros. - Say N if unsure. - config PROFILE_ALL_BRANCHES bool "Profile all if conditionals" - depends on TRACE_BRANCH_PROFILING + select TRACE_BRANCH_PROFILING help This tracer profiles all branch conditions. Every if () taken in the kernel is recorded whether it hit or miss. @@ -235,11 +261,12 @@ config PROFILE_ALL_BRANCHES /debugfs/tracing/profile_branch + This option also enables the likely/unlikely profiler. + This configuration, when enabled, will impose a great overhead on the system. This should only be enabled when the system is to be analyzed - - Say N if unsure. +endchoice config TRACING_BRANCHES bool -- 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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