Science Forums 2

[alexander]

just put up my third system on this

this one is nix, and its supposed to run transparently (shhh)

my biggest problem is that on nix, boinc has not provided a way to limit cpu usage, and for me, it's a big deal, when i am installing it on a future router....

i think i may have found a solution though

//cpulimit.c
/**
* Simple program to limit the cpu usage of a process
*
* Author: Angelo Marletta (marlonx80@hotmail.com)
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/resource.h>

//pid of the controlled process
int pid;

//SIGINT signal handler
void quit(int sig) {
//let the process continue if it's stopped
kill(pid,SIGCONT);
exit(0);
}

int main(int argc, char **argv) {

if (argc!=3) {
fprintf(stderr,"Usage: %s {pid} {max cpu percentage}n",argv[0]);
exit(1);
}
pid=atoi(argv[1]);
int limit=atoi(argv[2]);
if (limit>100 || limit<0) {
fprintf(stderr,"limit must be in the range 0-100n");
exit(1);
}
//if possible renice this process, so it has more responsiveness
if (setpriority(PRIO_PROCESS,getpid(),-20)!=0) {
printf("Warning: cannot renice.nTo work better you should run this program as root.n");
}
signal(SIGINT,quit);

//time quantum in microseconds
int period=100000;
struct timespec twork,tsleep; //time to work, and time to sleep
twork.tv_sec=0;
twork.tv_nsec=period*limit*10;
tsleep.tv_sec=0;
tsleep.tv_nsec=period*(100-limit)*10;

while(1) {
if (kill(pid,SIGSTOP)!=0) break;
nanosleep(&tsleep,NULL);
if (kill(pid,SIGCONT)!=0) break;
nanosleep(&twork,NULL);
}

perror("kill()");
exit(1);
}