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| author | Witold Baryluk <baryluk@smp.if.uj.edu.pl> | 2009-03-17 21:15:44 +0100 |
|---|---|---|
| committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-17 23:10:43 -0400 |
| commit | 97e7e4f391cac2b00417b581b432533d245d4fd0 (patch) | |
| tree | d51d4776962f5838f4cb4cc804d2c94db185527d /include/linux/compiler.h | |
| parent | af4617bdba34aa556272b34c3986b0a4d588f568 (diff) | |
| download | blackbird-obmc-linux-97e7e4f391cac2b00417b581b432533d245d4fd0.tar.gz blackbird-obmc-linux-97e7e4f391cac2b00417b581b432533d245d4fd0.zip | |
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 <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 6 |
1 files 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 */ |
