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| author | Rong Xu <xur@google.com> | 2013-10-03 17:13:50 +0000 |
|---|---|---|
| committer | Rong Xu <xur@gcc.gnu.org> | 2013-10-03 17:13:50 +0000 |
| commit | 942df7390fb64e26bb7ed6ac58ee9911be4ea5cb (patch) | |
| tree | 48352394b524e6a8198bc62633939861961f8a7e /gcc/params.def | |
| parent | 2ef7251f6cd9e228cafa3473929ff55c9cb56928 (diff) | |
| download | gcc-942df7390fb64e26bb7ed6ac58ee9911be4ea5cb.zip gcc-942df7390fb64e26bb7ed6ac58ee9911be4ea5cb.tar.gz gcc-942df7390fb64e26bb7ed6ac58ee9911be4ea5cb.tar.bz2 | |
predict.c (tree_predict_by_opcode): Get the probability for builtin_expect from param builtin_expect_probability.
* predict.c (tree_predict_by_opcode): Get the probability
for builtin_expect from param builtin_expect_probability.
* params.def (BUILTIN_EXPECT_PROBABILITY): New parameter.
* predict.def (PRED_BUILTIN_EXPECT_RELAXED): Fix comments.
* doc/invoke.texi: Add documentation for builtin-expect-probability.
* gcc.target/i386/cold-attribute-2.c: Fix the test by using original
probability.
* gcc.dg/tree-ssa/ipa-split-5.c: Ditto.
* gcc.dg/tree-ssa/ipa-split-6.c: Ditto.
--This li (t)ene, and those below, will be ignored--
M gcc/params.def
M gcc/predict.def
M gcc/ChangeLog
M gcc/testsuite/gcc.dg/tree-ssa/ipa-split-5.c
M gcc/testsuite/gcc.dg/tree-ssa/ipa-split-6.c
M gcc/testsuite/gcc.target/i386/cold-attribute-2.c
M gcc/predict.c
M gcc/doc/invoke.texi
From-SVN: r203167
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", |