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author | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
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committer | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
commit | 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch) | |
tree | 4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/benchtests/bench-util.c | |
parent | 199fc19d3aaaf57944ef036e15904febe877fc93 (diff) | |
download | glibc-zack/build-layout-experiment.tar.gz glibc-zack/build-layout-experiment.tar.xz glibc-zack/build-layout-experiment.zip |
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/benchtests/bench-util.c')
-rw-r--r-- | REORG.TODO/benchtests/bench-util.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/REORG.TODO/benchtests/bench-util.c b/REORG.TODO/benchtests/bench-util.c new file mode 100644 index 0000000000..0dd75b7d8d --- /dev/null +++ b/REORG.TODO/benchtests/bench-util.c @@ -0,0 +1,34 @@ +/* Benchmark utility functions. + Copyright (C) 2015-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + + +static volatile unsigned int dontoptimize = 0; + +void +bench_start (void) +{ + /* This loop should cause CPU to switch to maximal freqency. + This makes subsequent measurement more accurate. We need a side effect + to prevent the loop being deleted by compiler. + This should be enough to cause CPU to speed up and it is simpler than + running loop for constant time. This is used when user does not have root + access to set a constant freqency. */ + + for (int k = 0; k < START_ITER; k++) + dontoptimize += 23 * dontoptimize + 2; +} |