Re: [PATCH] tracing/branch-tracer: PROFILE_BRANCHES_PER_CPU must depend on SMP

Steven Rostedt
2009-06-06T14:42:37Z

On Sat, 6 Jun 2009, Frederic Weisbecker wrote:
>
> [ Impact: fix a build failure with the branch tracer ]
>
> Reported-by: Ingo Molnar <mingo@elte.hu>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> ---
> kernel/trace/Kconfig | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 309a264..0efbcc5 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -285,7 +285,7 @@ endchoice
>
> config PROFILE_BRANCHES_PER_CPU
> bool "Profile branches on a per cpu basis"
> - depends on PROFILE_ALL_BRANCHES
> + depends on PROFILE_ALL_BRANCHES && SMP

You just wasted two minutes of my time!

I was just about to send out the same patch, but you beat me to it. ;-)

Acked-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

> help
> When profiling all branches, the system can take a big cache line
> bouncing hit. On boxes with lots of CPUs, this can slow the system
> --
> 1.6.2.3
>
>