109 lines
2.2 KiB
C
109 lines
2.2 KiB
C
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/*
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*
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* Copyright (c) Novell Inc. 2011
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms in version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program 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
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* the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Author: Peter W. Morreale <pmorreale AT novell DOT com>
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* Date: 11/08/2011
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*/
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/*
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* Must be ported to OS's other than Linux
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*/
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#ifdef __linux__
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# define _GNU_SOURCE
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# include <sched.h>
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# include <stdio.h>
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static int set_affinity(int cpu)
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{
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cpu_set_t mask;
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CPU_ZERO(&mask);
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CPU_SET(cpu, &mask);
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return (sched_setaffinity(0, sizeof(cpu_set_t), &mask));
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}
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static int get_online_cpu_from_sysfs(void)
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{
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FILE *f;
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int cpu = -1;
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f = fopen("/sys/devices/system/cpu/online", "r");
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if (!f)
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return -1;
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fscanf(f, "%d", &cpu);
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fclose(f);
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return cpu;
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}
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static int get_online_cpu_from_cpuinfo(void)
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{
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FILE *f;
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int cpu = -1;
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char line[4096];
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f = fopen("/proc/cpuinfo", "r");
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if (!f)
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return -1;
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while (!feof(f)) {
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if (!fgets(line, sizeof(line), f))
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return -1;
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/*
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* cpuinfo output is not consistent across all archictures,
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* it can be "processor : N", but for example on s390
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* it's: "processor N: ...", so ignore any non-number
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* after "processor"
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*/
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if (sscanf(line, "processor%*[^0123456789]%d", &cpu) == 1)
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break;
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}
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fclose(f);
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return cpu;
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}
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static int set_affinity_single(void)
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{
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int cpu;
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cpu = get_online_cpu_from_sysfs();
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if (cpu >= 0)
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goto set_affinity;
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cpu = get_online_cpu_from_cpuinfo();
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if (cpu >= 0)
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goto set_affinity;
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fprintf(stderr, "WARNING: Failed to detect online cpu, using cpu=0\n");
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cpu = 0;
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set_affinity:
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return set_affinity(cpu);
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}
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#else
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#include <errno.h>
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static int set_affinity_single(void)
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{
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errno = ENOSYS;
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return -1;
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}
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#endif
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