* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//config:config TASKSET
+//config: bool "taskset"
+//config: default n # doesn't build on some non-x86 targets (m68k)
+//config: help
+//config: Retrieve or set a processes's CPU affinity.
+//config: This requires sched_{g,s}etaffinity support in your libc.
+//config:
+//config:config FEATURE_TASKSET_FANCY
+//config: bool "Fancy output"
+//config: default y
+//config: depends on TASKSET
+//config: help
+//config: Add code for fancy output. This merely silences a compiler-warning
+//config: and adds about 135 Bytes. May be needed for machines with alot
+//config: of CPUs.
+
+//applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP))
+//kbuild:lib-$(CONFIG_TASKSET) += taskset.o
+
+//usage:#define taskset_trivial_usage
+//usage: "[-p] [MASK] [PID | PROG ARGS]"
+//usage:#define taskset_full_usage "\n\n"
+//usage: "Set or get CPU affinity\n"
+//usage: "\n -p Operate on an existing PID"
+//usage:
+//usage:#define taskset_example_usage
+//usage: "$ 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"
+/*
+ Not yet implemented:
+ * -a/--all-tasks (affect all threads)
+ * -c/--cpu-list (specify CPUs via "1,3,5-7")
+ */
+
#include <sched.h>
#include "libbb.h"
#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
+ BUILD_BUG_ON(CPU_SETSIZE < 8*sizeof(int));
+
+ /* Take the least significant bits. Assume cpu_set_t is
+ * implemented as an array of unsigned long or unsigned
+ * int.
*/
-#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;
+ if (CPU_SETSIZE < 8*sizeof(long))
+ return *(unsigned*)mask;
+ if (CPU_SETSIZE < 8*sizeof(long long))
+ return *(unsigned long*)mask;
+# if BB_BIG_ENDIAN
+ if (sizeof(long long) > sizeof(long)) {
+ /* We can put two long in the long long, but they have to
+ * be swapped: the least significant word comes first in the
+ * array */
+ unsigned long *p = (void*)mask;
+ return p[0] + ((unsigned long long)p[1] << (8*sizeof(long)));
+ }
+# endif
+ return *(unsigned long long*)mask;
}
#endif
current_new += 8; /* "new" */
}
- { /* Affinity was specified, translate it into cpu_set_t */
+ /* Affinity was specified, translate it into cpu_set_t */
+ CPU_ZERO(&mask);
+ if (!ENABLE_FEATURE_TASKSET_FANCY) {
unsigned i;
+ unsigned long long m;
+
/* 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 };
+ m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
+ i = 0;
+ do {
+ if (m & 1)
+ CPU_SET(i, &mask);
+ i++;
+ m >>= 1;
+ } while (m != 0);
+ } else {
+ unsigned i;
+ char *last_byte;
+ char *bin;
+ uint8_t bit_in_byte;
+
+ /* Cheap way to get "long enough" buffer */
+ bin = xstrdup(aff);
+
+ if (aff[0] != '0' || (aff[1]|0x20) != 'x') {
+/* TODO: decimal/octal masks are still limited to 2^64 */
+ unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
+ bin += strlen(bin);
+ last_byte = bin - 1;
+ while (m) {
+ *--bin = m & 0xff;
+ m >>= 8;
+ }
+ } else {
+ /* aff is "0x.....", we accept very long masks in this form */
+ last_byte = hex2bin(bin, aff + 2, INT_MAX);
+ if (!last_byte) {
+ bad_aff:
+ bb_error_msg_and_die("bad affinity '%s'", aff);
+ }
+ last_byte--; /* now points to the last byte */
+ }
- CPU_ZERO(&mask);
- for (i = 0; i < CNT_BIT; i++) {
- unsigned long long bit = (1ULL << i);
- if (bit & m)
+ i = 0;
+ bit_in_byte = 1;
+ while (last_byte >= bin) {
+ if (bit_in_byte & *last_byte) {
+ if (i >= CPU_SETSIZE)
+ goto bad_aff;
CPU_SET(i, &mask);
+ //bb_error_msg("bit %d set", i);
+ }
+ i++;
+ /* bit_in_byte is uint8_t! & 0xff is implied */
+ bit_in_byte = (bit_in_byte << 1);
+ if (!bit_in_byte) {
+ bit_in_byte = 1;
+ last_byte--;
+ }
}
}
projects / oweals / busybox.git / blobdiff