/* vi: set sw=4 ts=4: */
/*
* taskset - retrieve or set a processes' CPU affinity
- * Copyright (c) 2006 Bernhard Fischer
+ * Copyright (c) 2006 Bernhard Reutner-Fischer
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//usage:#define taskset_trivial_usage
+//usage: "[-p] [MASK] [PID | PROG ARGS]"
+//usage:#define taskset_full_usage "\n\n"
+//usage: "Set or get CPU affinity\n"
+//usage: "\n -p Operate on an existing PID"
+//usage:
+//usage:#define taskset_example_usage
+//usage: "$ taskset 0x7 ./dgemm_test&\n"
+//usage: "$ taskset -p 0x1 $!\n"
+//usage: "pid 4790's current affinity mask: 7\n"
+//usage: "pid 4790's new affinity mask: 1\n"
+//usage: "$ taskset 0x7 /bin/sh -c './taskset -p 0x1 $$'\n"
+//usage: "pid 6671's current affinity mask: 1\n"
+//usage: "pid 6671's new affinity mask: 1\n"
+//usage: "$ taskset -p 1\n"
+//usage: "pid 1's current affinity mask: 3\n"
+
#include <sched.h>
-#include <getopt.h> /* optind */
#include "libbb.h"
#if ENABLE_FEATURE_TASKSET_FANCY
#define TASKSET_PRINTF_MASK "%s"
-#define from_cpuset(x) __from_cpuset(&x)
/* craft a string from the mask */
-static char *__from_cpuset(cpu_set_t *mask)
+static char *from_cpuset(cpu_set_t *mask)
{
int i;
- char *ret = 0, *str = xzalloc(9);
+ char *ret = NULL;
+ char *str = xzalloc((CPU_SETSIZE / 4) + 1); /* we will leak it */
for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) {
- char val = 0;
+ int val = 0;
int off;
for (off = 0; off <= 3; ++off)
- if (CPU_ISSET(i+off, mask))
- val |= 1<<off;
-
+ if (CPU_ISSET(i + off, mask))
+ val |= 1 << off;
if (!ret && val)
ret = str;
- *str++ = (val-'0'<=9) ? (val+48) : (val+87);
+ *str++ = bb_hexdigits_upcase[val] | 0x20;
}
return ret;
}
#else
-#define TASKSET_PRINTF_MASK "%x"
-/* (void*) cast is for battling gcc: */
-/* "dereferencing type-punned pointer will break strict-aliasing rules" */
-#define from_cpuset(mask) (*(unsigned*)(void*)&(mask))
+#define TASKSET_PRINTF_MASK "%llx"
+static unsigned long long from_cpuset(cpu_set_t *mask)
+{
+ struct BUG_CPU_SETSIZE_is_too_small {
+ char BUG_CPU_SETSIZE_is_too_small[
+ CPU_SETSIZE < sizeof(int) ? -1 : 1];
+ };
+ char *p = (void*)mask;
+
+ /* Take the least significant bits. Careful!
+ * Consider both CPU_SETSIZE=4 and CPU_SETSIZE=1024 cases
+ */
+#if BB_BIG_ENDIAN
+ /* For big endian, it means LAST bits */
+ if (CPU_SETSIZE < sizeof(long))
+ p += CPU_SETSIZE - sizeof(int);
+ else if (CPU_SETSIZE < sizeof(long long))
+ p += CPU_SETSIZE - sizeof(long);
+ else
+ p += CPU_SETSIZE - sizeof(long long);
+#endif
+ if (CPU_SETSIZE < sizeof(long))
+ return *(unsigned*)p;
+ if (CPU_SETSIZE < sizeof(long long))
+ return *(unsigned long*)p;
+ return *(unsigned long long*)p;
+}
#endif
int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int taskset_main(int argc ATTRIBUTE_UNUSED, char **argv)
+int taskset_main(int argc UNUSED_PARAM, char **argv)
{
cpu_set_t mask;
pid_t pid = 0;
char *pid_str;
char *aff = aff; /* for compiler */
+ /* NB: we mimic util-linux's taskset: -p does not take
+ * an argument, i.e., "-pN" is NOT valid, only "-p N"!
+ * Indeed, util-linux-2.13-pre7 uses:
+ * getopt_long(argc, argv, "+pchV", ...), not "...p:..." */
+
opt_complementary = "-1"; /* at least 1 arg */
opt_p = getopt32(argv, "+p");
argv += optind;
if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
- pid, current_new, from_cpuset(mask));
+ pid, current_new, from_cpuset(&mask));
if (!*argv) {
/* Either it was just "-p <pid>",
* or it was "-p <aff> <pid>" and we came here
unsigned i;
/* Do not allow zero mask: */
unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
+ enum { CNT_BIT = CPU_SETSIZE < sizeof(m)*8 ? CPU_SETSIZE : sizeof(m)*8 };
+
CPU_ZERO(&mask);
- for (i = 0; i < CPU_SETSIZE; i++) {
+ for (i = 0; i < CNT_BIT; i++) {
unsigned long long bit = (1ULL << i);
if (bit & m)
CPU_SET(i, &mask);
if (sched_setaffinity(pid, sizeof(mask), &mask))
bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
- if (!*argv) /* "-p <aff> <pid> [...ignored...]" */
+ if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
goto print_aff; /* print new affinity and exit */
- BB_EXECVP(*argv, argv);
- bb_simple_perror_msg_and_die(*argv);
+ BB_EXECVP_or_die(argv);
}