222 lines
6.2 KiB
C
222 lines
6.2 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* taskset - retrieve or set a processes' CPU affinity
|
|
* Copyright (c) 2006 Bernhard Reutner-Fischer
|
|
*
|
|
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
|
|
*/
|
|
|
|
//config:config TASKSET
|
|
//config: bool "taskset"
|
|
//config: default y
|
|
//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: Needed for machines with more than 32-64 CPUs:
|
|
//config: affinity parameter 0xHHHHHHHHHHHHHHHHHHHH can be arbitrarily long
|
|
//config: in this case. Otherwise, it is limited to sizeof(long).
|
|
|
|
//applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP))
|
|
//kbuild:lib-$(CONFIG_TASKSET) += taskset.o
|
|
|
|
//usage:#define taskset_trivial_usage
|
|
//usage: "[-p] [HEXMASK] PID | PROG ARGS"
|
|
//usage:#define taskset_full_usage "\n\n"
|
|
//usage: "Set or get CPU affinity\n"
|
|
//usage: "\n -p Operate on an existing PID"
|
|
//usage:
|
|
//usage:#define taskset_example_usage
|
|
//usage: "$ 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)
|
|
* needs to get TIDs from /proc/PID/task/ and use _them_ as "pid" in sched_setaffinity(pid)
|
|
* -c/--cpu-list (specify CPUs via "1,3,5-7")
|
|
*/
|
|
|
|
#include <sched.h>
|
|
#include "libbb.h"
|
|
|
|
typedef unsigned long ul;
|
|
#define SZOF_UL (unsigned)(sizeof(ul))
|
|
#define BITS_UL (unsigned)(sizeof(ul)*8)
|
|
#define MASK_UL (unsigned)(sizeof(ul)*8 - 1)
|
|
|
|
#if ENABLE_FEATURE_TASKSET_FANCY
|
|
#define TASKSET_PRINTF_MASK "%s"
|
|
/* craft a string from the mask */
|
|
static char *from_mask(const ul *mask, unsigned sz_in_bytes)
|
|
{
|
|
char *str = xzalloc((sz_in_bytes+1) * 2); /* we will leak it */
|
|
char *p = str;
|
|
for (;;) {
|
|
ul v = *mask++;
|
|
if (SZOF_UL == 4)
|
|
p += sprintf(p, "%08lx", v);
|
|
if (SZOF_UL == 8)
|
|
p += sprintf(p, "%016lx", v);
|
|
if (SZOF_UL == 16)
|
|
p += sprintf(p, "%032lx", v); /* :) */
|
|
sz_in_bytes -= SZOF_UL;
|
|
if ((int)sz_in_bytes <= 0)
|
|
break;
|
|
}
|
|
while (str[0] == '0' && str[1])
|
|
str++;
|
|
return str;
|
|
}
|
|
#else
|
|
#define TASKSET_PRINTF_MASK "%lx"
|
|
static unsigned long long from_mask(ul *mask, unsigned sz_in_bytes UNUSED_PARAM)
|
|
{
|
|
return *mask;
|
|
}
|
|
#endif
|
|
|
|
static unsigned long *get_aff(int pid, unsigned *sz)
|
|
{
|
|
int r;
|
|
unsigned long *mask = NULL;
|
|
unsigned sz_in_bytes = *sz;
|
|
|
|
for (;;) {
|
|
mask = xrealloc(mask, sz_in_bytes);
|
|
r = sched_getaffinity(pid, sz_in_bytes, (void*)mask);
|
|
if (r == 0)
|
|
break;
|
|
sz_in_bytes *= 2;
|
|
if (errno == EINVAL && (int)sz_in_bytes > 0)
|
|
continue;
|
|
bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
|
|
}
|
|
//bb_error_msg("get mask[0]:%lx sz_in_bytes:%d", mask[0], sz_in_bytes);
|
|
*sz = sz_in_bytes;
|
|
return mask;
|
|
}
|
|
|
|
int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int taskset_main(int argc UNUSED_PARAM, char **argv)
|
|
{
|
|
ul *mask;
|
|
unsigned mask_size_in_bytes;
|
|
pid_t pid = 0;
|
|
unsigned opt_p;
|
|
const char *current_new;
|
|
char *aff;
|
|
|
|
/* 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;
|
|
|
|
aff = *argv++;
|
|
if (opt_p) {
|
|
char *pid_str = aff;
|
|
if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
|
|
pid_str = *argv; /* NB: *argv != NULL in this case */
|
|
}
|
|
/* else it was just "-p <pid>", and *argv == NULL */
|
|
pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
|
|
} else {
|
|
/* <aff> <cmd...> */
|
|
if (!*argv)
|
|
bb_show_usage();
|
|
}
|
|
|
|
mask_size_in_bytes = SZOF_UL;
|
|
current_new = "current";
|
|
print_aff:
|
|
mask = get_aff(pid, &mask_size_in_bytes);
|
|
if (opt_p) {
|
|
printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
|
|
pid, current_new, from_mask(mask, mask_size_in_bytes));
|
|
if (*argv == NULL) {
|
|
/* Either it was just "-p <pid>",
|
|
* or it was "-p <aff> <pid>" and we came here
|
|
* for the second time (see goto below) */
|
|
return EXIT_SUCCESS;
|
|
}
|
|
*argv = NULL;
|
|
current_new = "new";
|
|
}
|
|
memset(mask, 0, mask_size_in_bytes);
|
|
|
|
/* Affinity was specified, translate it into mask */
|
|
/* it is always in hex, skip "0x" if it exists */
|
|
if (aff[0] == '0' && (aff[1]|0x20) == 'x')
|
|
aff += 2;
|
|
|
|
if (!ENABLE_FEATURE_TASKSET_FANCY) {
|
|
mask[0] = xstrtoul(aff, 16);
|
|
} else {
|
|
unsigned i;
|
|
char *last_char;
|
|
|
|
i = 0; /* bit pos in mask[] */
|
|
|
|
/* aff is ASCII hex string, accept very long masks in this form.
|
|
* Process hex string AABBCCDD... to ulong mask[]
|
|
* from the rightmost nibble, which is least-significant.
|
|
* Bits not fitting into mask[] are ignored: (example: 1234
|
|
* in 12340000000000000000000000000000000000000ff)
|
|
*/
|
|
last_char = strchrnul(aff, '\0');
|
|
while (last_char > aff) {
|
|
char c;
|
|
ul val;
|
|
|
|
last_char--;
|
|
c = *last_char;
|
|
if (isdigit(c))
|
|
val = c - '0';
|
|
else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
|
|
val = (c|0x20) - ('a' - 10);
|
|
else
|
|
bb_error_msg_and_die("bad affinity '%s'", aff);
|
|
|
|
if (i < mask_size_in_bytes * 8) {
|
|
mask[i / BITS_UL] |= val << (i & MASK_UL);
|
|
//bb_error_msg("bit %d set", i);
|
|
}
|
|
/* else:
|
|
* We can error out here, but we don't.
|
|
* For one, kernel itself ignores bits in mask[]
|
|
* which do not map to any CPUs:
|
|
* if mask[] has one 32-bit long element,
|
|
* but you have only 8 CPUs, all bits beyond first 8
|
|
* are ignored, silently.
|
|
* No point in making bits past 31th to be errors.
|
|
*/
|
|
i += 4;
|
|
}
|
|
}
|
|
|
|
/* Set pid's or our own (pid==0) affinity */
|
|
if (sched_setaffinity(pid, mask_size_in_bytes, (void*)mask))
|
|
bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
|
|
//bb_error_msg("set mask[0]:%lx", mask[0]);
|
|
|
|
if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
|
|
goto print_aff; /* print new affinity and exit */
|
|
|
|
BB_EXECVP_or_die(argv);
|
|
}
|