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4a1995267e
2000-04-12 Andreas Jaeger <aj@suse.de> * sysdeps/unix/i386/i586/clock_gettime.c: Fix typo. * sysdeps/unix/sysv/linux/i386/get_clockfreq.c: Include <string.h> for memmem declaration. * sysdeps/unix/clock_gettime.c (clock_gettime): Initialize retval to -1. * sysdeps/posix/clock_getres.c (clock_getres): Likewise.
79 lines
2.2 KiB
C
79 lines
2.2 KiB
C
/* Get frequency of the system processor. i386/Linux version.
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Copyright (C) 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <ctype.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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unsigned long long int
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__get_clockfreq (void)
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{
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/* We read the information from the /proc filesystem. It contains at
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least one line like
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cpu MHz : 497.840237
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We search for this line and convert the number in an integer. */
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static unsigned long long int result;
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int fd;
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/* If this function was called before, we know the result. */
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if (result != 0)
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return result;
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fd = open ("/proc/cpuinfo", O_RDONLY);
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if (__builtin_expect (fd != -1, 1))
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{
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/* XXX AFAIK the /proc filesystem can generate "files" only up
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to a size of 4096 bytes. */
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char buf[4096];
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ssize_t n;
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n = read (fd, buf, sizeof buf);
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if (__builtin_expect (n, 1) > 0)
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{
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char *mhz = memmem (buf, n, "cpu MHz", 7);
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if (__builtin_expect (mhz != NULL, 1))
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{
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char *endp = buf + n;
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/* Search for the beginning of the string. */
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while (mhz < endp && (*mhz < '0' || *mhz > '9') && *mhz != '\n')
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++mhz;
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while (mhz < endp && *mhz != '\n')
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{
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if (*mhz >= '0' && *mhz <= '9')
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{
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result *= 10;
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result += *mhz - '0';
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}
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++mhz;
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}
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}
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}
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close (fd);
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}
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return result;
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}
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