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docs/cpu-load: format the example code.

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format the example code.

Signed-off-by: Hui Su <sh_def@163.com>
Link: https://lore.kernel.org/r/20201018170557.GA7670@rlk
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Hui Su 2020-10-19 01:05:57 +08:00 committed by Jonathan Corbet
parent 4fb220da0d
commit bb7a2c6362
1 changed files with 30 additions and 27 deletions
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57
Documentation/admin-guide/cpu-load.rst
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@ -61,43 +61,46 @@ will lead to quite erratic information inside ``/proc/stat``::
static volatile sig_atomic_t stop; static volatile sig_atomic_t stop;
static void sighandler (int signr) static void sighandler(int signr)
{ {
(void) signr; (void) signr;
stop = 1; stop = 1;
} }
static unsigned long hog (unsigned long niters) static unsigned long hog (unsigned long niters)
{ {
stop = 0; stop = 0;
while (!stop && --niters); while (!stop && --niters);
return niters; return niters;
} }
int main (void) int main (void)
{ {
int i; int i;
struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 }, struct itimerval it = {
.it_value = { .tv_sec = 0, .tv_usec = 1 } }; .it_interval = { .tv_sec = 0, .tv_usec = 1 },
sigset_t set; .it_value = { .tv_sec = 0, .tv_usec = 1 } };
unsigned long v[HIST]; sigset_t set;
double tmp = 0.0; unsigned long v[HIST];
unsigned long n; double tmp = 0.0;
signal (SIGALRM, &sighandler); unsigned long n;
setitimer (ITIMER_REAL, &it, NULL); signal(SIGALRM, &sighandler);
setitimer(ITIMER_REAL, &it, NULL);
hog (ULONG_MAX); hog (ULONG_MAX);
for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog (ULONG_MAX); for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog(ULONG_MAX);
for (i = 0; i < HIST; ++i) tmp += v[i]; for (i = 0; i < HIST; ++i) tmp += v[i];
tmp /= HIST; tmp /= HIST;
n = tmp - (tmp / 3.0); n = tmp - (tmp / 3.0);
sigemptyset (&set); sigemptyset(&set);
sigaddset (&set, SIGALRM); sigaddset(&set, SIGALRM);
for (;;) { for (;;) {
hog (n); hog(n);
sigwait (&set, &i); sigwait(&set, &i);
} }
return 0; return 0;
} }