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Diffstat (limited to 'gcc/params.def')
| -rw-r--r-- | gcc/params.def | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/gcc/params.def b/gcc/params.def index 2749137..ff9ba9a 100644 --- a/gcc/params.def +++ b/gcc/params.def @@ -398,6 +398,19 @@ DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS, "max-predicted-iterations", "The maximum number of loop iterations we predict statically", 100, 0, 0) + +/* This parameter controls the probability of builtin_expect. The default + value is 90%. This empirical value is obtained through the weighted + probability of FDO counters (with the FDO count value as the weight) + in some real world programs: + (1) Google performance test benchmarks: the probability is 0.9081. + (2) Linux 3.3 kernel running Google search workload: the probability + is 0.8717. */ + +DEFPARAM(BUILTIN_EXPECT_PROBABILITY, + "builtin-expect-probability", + "Set the estimated probability in percentage for builtin expect. The default value is 90% probability.", + 90, 0, 100) DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK, "tracer-dynamic-coverage-feedback", "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available", |