luo980/libuv
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

linux: use CLOCK_BOOTTIME if available

Browse Source 
Use CLOCK_BOOTTIME to calculate the system uptime. Fall back to CLOCK_MONOTONIC
if CLOCK_BOOTTIME is not available (all pre-2.6.39 kernels).

The problem with CLOCK_MONOTONIC is that it doesn't increase when the system is
suspended, making the uptime differ from what the uptime(1) tool reports.
This commit is contained in:
Ben Noordhuis 2012-03-19 07:40:50 -07:00
parent 379ca428ef
commit 49d4e1884b
1 changed files with 26 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/unix/linux/core.c
View File

@ -48,6 +48,14 @@
#undef NANOSEC
#define NANOSEC 1000000000
/* This is rather annoying: CLOCK_BOOTTIME lives in <linux/time.h> but we can't
* include that file because it conflicts with <time.h>. We'll just have to
* define it ourselves.
*/
#ifndef CLOCK_BOOTTIME
# define CLOCK_BOOTTIME 7
#endif
static char buf[MAXPATHLEN + 1];
static struct {
@ -267,22 +275,28 @@ error:
uv_err_t uv_uptime(double* uptime) {
#ifdef CLOCK_MONOTONIC
static volatile int no_clock_boottime;
struct timespec now;
if (0 == clock_gettime(CLOCK_MONOTONIC, &now)) {
*uptime = now.tv_sec;
*uptime += (double)now.tv_nsec / 1000000000.0;
return uv_ok_;
int r;
/* Try CLOCK_BOOTTIME first, fall back to CLOCK_MONOTONIC if not available
* (pre-2.6.39 kernels). CLOCK_MONOTONIC doesn't increase when the system
* is suspended.
*/
if (no_clock_boottime) {
retry: r = clock_gettime(CLOCK_MONOTONIC, &now);
}
return uv__new_sys_error(errno);
#else
struct sysinfo info;
if (sysinfo(&info) < 0) {
else if ((r = clock_gettime(CLOCK_BOOTTIME, &now)) && errno == EINVAL) {
no_clock_boottime = 1;
goto retry;
}
if (r)
return uv__new_sys_error(errno);
}
*uptime = (double)info.uptime;
*uptime = now.tv_sec;
*uptime += (double)now.tv_nsec / 1000000000.0;
return uv_ok_;
#endif
}