mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
35 lines
1.3 KiB
C
35 lines
1.3 KiB
C
/* 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;
|
|
}
|