| /* taskset.c - Retrieve or set the CPU affinity of a process. |
| * |
| * Copyright 2012 Elie De Brauwer <eliedebrauwer@gmail.com> |
| |
| USE_TASKSET(NEWTOY(taskset, "<1^pa", TOYFLAG_BIN|TOYFLAG_STAYROOT)) |
| |
| config TASKSET |
| bool "taskset" |
| default y |
| help |
| usage: taskset [-ap] [mask] [PID | cmd [args...]] |
| |
| Launch a new task which may only run on certain processors, or change |
| the processor affinity of an exisitng PID. |
| |
| Mask is a hex string where each bit represents a processor the process |
| is allowed to run on. PID without a mask displays existing affinity. |
| |
| -p Set/get the affinity of given PID instead of a new command. |
| -a Set/get the affinity of all threads of the PID. |
| */ |
| |
| #define FOR_taskset |
| #include "toys.h" |
| |
| #include <sys/syscall.h> |
| #define sched_setaffinity(pid, size, cpuset) \ |
| syscall(__NR_sched_setaffinity, (pid_t)pid, (size_t)size, (void *)cpuset) |
| #define sched_getaffinity(pid, size, cpuset) \ |
| syscall(__NR_sched_getaffinity, (pid_t)pid, (size_t)size, (void *)cpuset) |
| |
| // mask is an array of long, which makes the layout a bit weird on big |
| // endian systems but as long as it's consistent... |
| |
| static void do_taskset(pid_t pid, int quiet) |
| { |
| unsigned long *mask = (unsigned long *)toybuf; |
| char *s = *toys.optargs, *failed = "failed to %s %d's affinity"; |
| int i, j, k; |
| |
| for (i=0; ; i++) { |
| if (!quiet) { |
| int j = sizeof(toybuf), flag = 0; |
| |
| if (-1 == sched_getaffinity(pid, sizeof(toybuf), (void *)mask)) |
| perror_exit(failed, "get", pid); |
| |
| printf("pid %d's %s affinity mask: ", pid, i ? "new" : "current"); |
| |
| while (j--) { |
| int x = 255 & (mask[j/sizeof(long)] >> (8*(j&(sizeof(long)-1)))); |
| |
| if (flag) printf("%02x", x); |
| else if (x) { |
| flag++; |
| printf("%x", x); |
| } |
| } |
| putchar('\n'); |
| } |
| |
| if (i || toys.optc < 2) return; |
| |
| memset(toybuf, 0, sizeof(toybuf)); |
| k = strlen(s = *toys.optargs); |
| s += k; |
| for (j = 0; j<k; j++) { |
| unsigned long digit = *(--s) - '0'; |
| |
| if (digit > 9) digit = 10 + tolower(*s)-'a'; |
| if (digit > 15) error_exit("bad mask '%s'", *toys.optargs); |
| mask[j/(2*sizeof(long))] |= digit << 4*(j&((2*sizeof(long))-1)); |
| } |
| |
| if (-1 == sched_setaffinity(pid, sizeof(toybuf), (void *)mask)) |
| perror_exit(failed, "set", pid); |
| } |
| } |
| |
| static int task_callback(struct dirtree *new) |
| { |
| if (!new->parent) return DIRTREE_RECURSE; |
| if (isdigit(*new->name)) do_taskset(atoi(new->name), 0); |
| |
| return 0; |
| } |
| |
| void taskset_main(void) |
| { |
| if (!(toys.optflags & FLAG_p)) { |
| if (toys.optc < 2) error_exit("Needs 2 args"); |
| do_taskset(getpid(), 1); |
| xexec_optargs(1); |
| } else { |
| char *c; |
| pid_t pid = strtol(toys.optargs[toys.optc-1], &c, 10); |
| |
| if (*c) error_exit("Not int %s", toys.optargs[1]); |
| |
| if (toys.optflags & FLAG_a) { |
| char buf[33]; |
| sprintf(buf, "/proc/%ld/task/", (long)pid); |
| dirtree_read(buf, task_callback); |
| } else do_taskset(pid, 0); |
| } |
| } |