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taskset: add support for taking/printing CPU list (-c option)

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function                                             old     new   delta
taskset_main                                         511     855    +344

Based on patch by Fryderyk Wrobel <frd1996@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2019-11-01 15:44:49 +01:00
parent 21806562ca
commit 162ac7f45e
1 changed files with 118 additions and 11 deletions
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129
util-linux/taskset.c
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@ -20,6 +20,14 @@
//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).
//config:
//config:config FEATURE_TASKSET_CPULIST
//config: bool "CPU list support (-c option)"
//config: default y
//config: depends on FEATURE_TASKSET_FANCY
//config: help
//config: Add support for taking/printing affinity as CPU list when '-c'
//config: option is used. For example, it prints '0-3,7' instead of mask '8f'.
//applet:IF_TASKSET(APPLET_NOEXEC(taskset, taskset, BB_DIR_USR_BIN, BB_SUID_DROP, taskset))
@ -108,26 +116,109 @@ static unsigned long *get_aff(int pid, unsigned *sz)
return mask;
}
#if ENABLE_FEATURE_TASKSET_CPULIST
/*
* Parse the CPU list and set the mask accordingly.
*
* The list element can be either a CPU index or a range of CPU indices.
* Example: "1,3,5-7".
*
* note1: pattern specifiers after a range (e.g. 0-255:2/64) are not supported
* note2: leading/trailing white-spaces are not allowed
*/
static void parse_cpulist(ul *mask, unsigned max, char *s)
{
char *aff = s;
for (;;) {
unsigned bit, end;
bit = end = bb_strtou(s, &s, 10);
if (*s == '-') {
s++;
end = bb_strtou(s, &s, 10);
}
if ((*s != ',' && *s != '\0')
|| bit > end
|| end == UINT_MAX /* bb_strtou returns this on malformed / ERANGE numbers */
) {
bb_error_msg_and_die("bad affinity '%s'", aff);
}
while (bit <= end && bit < max) {
mask[bit / BITS_UL] |= (1UL << (bit & MASK_UL));
bit++;
}
if (*s == '\0')
break;
s++;
}
}
static void print_cpulist(const ul *mask, unsigned mask_size_in_bytes)
{
const ul *mask_end;
const char *delim;
unsigned pos;
ul bit;
mask_end = mask + mask_size_in_bytes / sizeof(mask[0]);
delim = "";
pos = 0;
bit = 1;
for (;;) {
if (*mask & bit) {
unsigned onebit = pos + 1;
printf("%s%u", delim, pos);
do {
pos++;
bit <<= 1;
if (bit == 0) {
mask++;
if (mask >= mask_end)
break;
bit = 1;
}
} while (*mask & bit);
if (onebit != pos)
printf("-%u", pos - 1);
delim = ",";
}
pos++;
bit <<= 1;
if (bit == 0) {
mask++;
if (mask >= mask_end)
break;
bit = 1;
}
}
bb_putchar('\n');
}
#endif
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;
unsigned opts;
enum {
OPT_p = 1 << 0,
OPT_c = (1 << 1) * ENABLE_FEATURE_TASKSET_CPULIST,
};
/* 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_p = getopt32(argv, "^+" "p" "\0" "-1" /* at least 1 arg */);
opts = getopt32(argv, "^+" "p"IF_FEATURE_TASKSET_CPULIST("c")
"\0" "-1" /* at least 1 arg */);
argv += optind;
aff = *argv++;
if (opt_p) {
if (opts & OPT_p) {
char *pid_str = aff;
if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
pid_str = *argv; /* NB: *argv != NULL in this case */
@ -144,8 +235,14 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
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",
if (opts & OPT_p) {
#if ENABLE_FEATURE_TASKSET_CPULIST
if (opts & OPT_c) {
printf("pid %d's %s affinity list: ", pid, current_new);
print_cpulist(mask, mask_size_in_bytes);
} else
#endif
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>",
@ -158,17 +255,27 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
}
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) {
/* 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;
mask[0] = xstrtoul(aff, 16);
} else {
}
#if ENABLE_FEATURE_TASKSET_CPULIST
else if (opts & OPT_c) {
parse_cpulist(mask, mask_size_in_bytes * 8, aff);
}
#endif
else {
unsigned i;
char *last_char;
/* 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;
i = 0; /* bit pos in mask[] */
/* aff is ASCII hex string, accept very long masks in this form.