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authorWitold Baryluk <baryluk@smp.if.uj.edu.pl>2009-03-17 23:15:44 +0300
committerSteven Rostedt <srostedt@redhat.com>2009-03-18 06:10:43 +0300
commit97e7e4f391cac2b00417b581b432533d245d4fd0 (patch)
treed51d4776962f5838f4cb4cc804d2c94db185527d /include/linux/compiler.h
parentaf4617bdba34aa556272b34c3986b0a4d588f568 (diff)
downloadlinux-97e7e4f391cac2b00417b581b432533d245d4fd0.tar.xz
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.h6
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 */