glibc/sysdeps/unix/sysv/linux/getloadavg.c

47 lines
1.5 KiB
C

/* Get system load averages. Linux version.
Copyright (C) 1999-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <array_length.h>
#include <sys/param.h>
#include <sys/sysinfo.h>
/* Put the 1 minute, 5 minute and 15 minute load averages
into the first NELEM elements of LOADAVG.
Return the number written (never more than 3, but may be less than NELEM),
or -1 if an error occurred. */
#define CLAMP(v, lo, hi) MIN (MAX (v, lo), hi)
#define SYSINFO_LOADS_SCALE (1 << SI_LOAD_SHIFT)
int
getloadavg (double loadavg[], int nelem)
{
struct sysinfo info;
if (__sysinfo (&info) != 0)
return -1;
nelem = CLAMP (nelem, 0, array_length (info.loads));
for (int i = 0; i < nelem; i++)
loadavg[i] = (double) info.loads[i] / SYSINFO_LOADS_SCALE;
return nelem;
}