127 lines
3.7 KiB
C++
127 lines
3.7 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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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 the
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GNU General Public License for more details.
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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, see <http://www.gnu.org/licenses/>.
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(c) 2011 Emanuele Oriani - ema at fastwebnet dot it
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*/
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#include <iostream>
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#include <cerrno>
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#include <cstdlib>
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#include <cstdio>
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static pid_t pid = -1;
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static int cpu = -1;
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static bool reset = false;
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static bool cpunum = false;
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// To get the number of available CPUs we run this
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// getaffinity BEFORE setting any affinity mask.
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// We will get all the available CPUs.
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static int num_cpus(void) {
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cpu_set_t cpu_set;
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CPU_ZERO(&cpu_set);
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const int max_cpus = 8*sizeof(cpu_set);
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if (0 == sched_getaffinity(getpid(), sizeof(cpu_set_t), &cpu_set)) {
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for(int i = 0; i < max_cpus; ++i)
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if (!CPU_ISSET(i, &cpu_set)) return i;
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}
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return max_cpus;
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}
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const int NCPUS = num_cpus();
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static void usage(const char *img) {
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std::cerr << img << ", a simple program to set CPU affinity on Linux." << std::endl;
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std::cerr << "(c) 2011 Emanuele Oriani - ema at fastwebnet dot it" << std::endl;
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std::cerr << "\nUsage:" << std::endl;
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std::cerr << " " << img << " [-p pid] [-c cpu] [-r]" << std::endl;
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std::cerr << " p: specify a process pid" << std::endl;
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std::cerr << " c: specify a cpu id (0-n)" << std::endl;
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std::cerr << " r: reset (enable all cpus)" << std::endl;
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std::cerr << " g: print cpus number" << std::endl;
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}
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static void opts(int argc, char *argv[]) {
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extern char *optarg;
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int res = -1;
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while(EOF != (res = getopt(argc, argv, "p:c:rhg"))) {
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switch((char)res) {
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case 'p':
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pid = (pid_t)std::atoi(optarg);
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break;
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case 'c':
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cpu = std::atoi(optarg);
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break;
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case 'r':
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reset = true;
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break;
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case 'g':
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cpunum = true;
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break;
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case 'h':
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default:
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usage(argv[0]);
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std::exit(-2);
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break;
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}
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}
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}
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int main(int argc, char *argv[]) {
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opts(argc, argv);
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cpu_set_t cpu_set;
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if (cpunum) std::cout << "Available cpus: " << NCPUS << '.' << std::endl;
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if (-1 == pid) pid = getpid();
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if (reset || (-1 != cpu)) {
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CPU_ZERO(&cpu_set);
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if (reset) {
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for(int i = 0; i < NCPUS; ++i)
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CPU_SET(i, &cpu_set);
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}
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else CPU_SET(cpu, &cpu_set);
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if (-1 == sched_setaffinity(pid, sizeof(cpu_set_t), &cpu_set)) {
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std::cerr << "Error : ";
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switch(errno) {
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case EFAULT:
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std::cerr << "A supplied memory address was invalid." << std::endl;
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std::exit(-1);
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break;
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case EINVAL:
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std::cerr << "The affinity bitmask mask contains no processors that are physically on the system, or cpusetsize is smaller than the size of the affinity mask used by the kernel." << std::endl;
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std::exit(-1);
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break;
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case EPERM:
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std::cerr << "The calling process does not have appropriate privileges." << std::endl;
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std::exit(-1);
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break;
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case ESRCH:
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std::cerr << "The process whose ID is " << pid << " could not be found." << std::endl;
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std::exit(-1);
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break;
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default:
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std::cerr << "Unknown error." << std::endl;
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std::exit(-1);
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break;
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}
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}
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}
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CPU_ZERO(&cpu_set);
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if (0 == sched_getaffinity(pid, sizeof(cpu_set_t), &cpu_set)) {
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std::cout << "Report:" << std::endl;
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for(int i = 0; i < NCPUS; ++i)
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if (CPU_ISSET(i, &cpu_set)) std::cout << "Cpu " << i << " is set." << std::endl;
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}
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}
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