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cpuset: add --count

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Can be used to count the number of hardware threads in the cpu set.

For example:
$ cpuset -g -p $$
pid 2440 mask: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,
35, 36, 37, 38, 39
pid 2440 domain policy: first-touch mask: 0, 1
$ cpuset -g --count -p $$
40

The intent is to replace calls to sysctl hw.ncpu and kern.smp.cpus which
can be found in the tree, which are not adequate given existence of
cpusets.

Right now only -g -p combination is supported to reduce complexity.
As anything else errors out, this can be expanded later as needed.

Differential Revision:	https://reviews.freebsd.org/D36351
This commit is contained in:
Mateusz Guzik 2023-02-04 17:47:41 +00:00
parent da6ae2cf17
commit d9d5f2c042
2 changed files with 65 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
usr.bin/cpuset/cpuset.1
View File

@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd July 3, 2018
.Dd August 25, 2022
.Dt CPUSET 1
.Os
.Sh NAME
@ -57,6 +57,10 @@
.Fl g
.Op Fl cir
.Op Fl d Ar domain | Fl j Ar jail | Fl p Ar pid | Fl t Ar tid | Fl s Ar setid | Fl x Ar irq
.Nm
.Fl g
.Fl -count
.Fl p Ar pid
.Sh DESCRIPTION
The
.Nm
@ -172,6 +176,16 @@ Specifies a thread id as the target of the operation.
.It Fl x Ar irq
Specifies an irq as the target of the operation.
.El
.Pp
The long options are as follows:
.Bl -tag -width ".Fl -count"
.It Fl -count
Count the number of hardware threads included in the set. Requires
.Fl g
and
.Fl p
flags.
.El
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES

51
usr.bin/cpuset/cpuset.c
View File

@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <getopt.h>
#include <jail.h>
#include <limits.h>
#include <stdio.h>
@ -52,6 +53,9 @@ __FBSDID("$FreeBSD$");
#include <unistd.h>
#include <string.h>
/*
* Short opts.
*/
static int Cflag;
static int cflag;
static int dflag;
@ -65,12 +69,24 @@ static int rflag;
static int sflag;
static int tflag;
static int xflag;
/*
* Long-only opts.
*/
static int count_flag;
static id_t id;
static cpulevel_t level;
static cpuwhich_t which;
#define OPT_THREADCOUNT (CHAR_MAX + 1)
static void usage(void);
static struct option long_opts[] = {
{ "count", no_argument, NULL, OPT_THREADCOUNT },
{ NULL, 0, NULL, 0 }
};
struct numa_policy {
const char *name;
int policy;
@ -283,6 +299,18 @@ printsetid(void)
levelnames[level], setid);
}
static void
printcpucount(void)
{
cpuset_t mask;
CPU_ZERO(&mask);
if (cpuset_getaffinity(CPU_LEVEL_ROOT, CPU_WHICH_PID, id,
sizeof(mask), &mask) != 0)
err(EXIT_FAILURE, "getaffinity");
printf("%d\n", CPU_COUNT(&mask));
}
int
main(int argc, char *argv[])
{
@ -300,7 +328,8 @@ main(int argc, char *argv[])
level = CPU_LEVEL_WHICH;
which = CPU_WHICH_PID;
id = pid = tid = setid = -1;
while ((ch = getopt(argc, argv, "Ccd:gij:l:n:p:rs:t:x:")) != -1) {
while ((ch = getopt_long(argc, argv,
"Ccd:gij:l:n:p:rs:t:x:", long_opts, NULL)) != -1) {
switch (ch) {
case 'C':
Cflag = 1;
@ -359,12 +388,30 @@ main(int argc, char *argv[])
which = CPU_WHICH_IRQ;
id = atoi(optarg);
break;
case OPT_THREADCOUNT:
count_flag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
/*
* count requires g and p flags and is incompatible with
* everything else for simplicity.
*/
if (count_flag) {
if (!gflag || !pflag)
usage();
if (Cflag || cflag || dflag || iflag || jflag || lflag ||
nflag || rflag || sflag || tflag || xflag)
usage();
printcpucount();
exit(EXIT_SUCCESS);
}
if (gflag) {
if (argc || Cflag || lflag || nflag)
usage();
@ -471,5 +518,7 @@ usage(void)
fprintf(stderr,
" cpuset -g [-cir]\n"
" [-d domain | -j jailid | -p pid | -t tid | -s setid | -x irq]\n");
fprintf(stderr,
" cpuset -g --count -p pid\n");
exit(1);
}