From 97e7e4f391cac2b00417b581b432533d245d4fd0 Mon Sep 17 00:00:00 2001 From: Witold Baryluk Date: Tue, 17 Mar 2009 21:15:44 +0100 Subject: [PATCH] tracing: optimization of branch tracer Impact: better performance for if branch tracer Use an array to count the hit and misses of a conditional instead of using another conditional. This cuts down on saturation of branch predictions and increases performance of modern pipelined architectures. Signed-off-by: Witold Baryluk Signed-off-by: Steven Rostedt --- include/linux/compiler.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index d95da1020f1c..6faa7e549de4 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -68,6 +68,7 @@ struct ftrace_branch_data { unsigned long miss; unsigned long hit; }; + unsigned long miss_hit[2]; }; }; @@ -125,10 +126,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); .line = __LINE__, \ }; \ ______r = !!(cond); \ - if (______r) \ - ______f.hit++; \ - else \ - ______f.miss++; \ + ______f.miss_hit[______r]++; \ ______r; \ })) #endif /* CONFIG_PROFILE_ALL_BRANCHES */