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darwin: work around clock jumping back in time

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It was reported that mach_absolute_time() can jump backward in time when
the machine is suspended. Use mach_continuous_time() when available to
work around that (macOS 10.12 and up.)

Fixes: https://github.com/libuv/libuv/issues/2891
PR-URL: https://github.com/libuv/libuv/pull/2894
Reviewed-By: Phil Willoughby <philwill@fb.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
This commit is contained in:
Ben Noordhuis 2020-07-01 10:32:57 +02:00
parent 41f57320ba
commit 4685be236b
1 changed files with 16 additions and 7 deletions
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23
src/unix/darwin.c
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@ -25,6 +25,7 @@
#include <stdint.h>
#include <errno.h>
#include <dlfcn.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <mach-o/dyld.h> /* _NSGetExecutablePath */
@ -32,6 +33,10 @@
#include <sys/sysctl.h>
#include <unistd.h> /* sysconf */
static uv_once_t once = UV_ONCE_INIT;
static uint64_t (*time_func)(void);
static mach_timebase_info_data_t timebase;
int uv__platform_loop_init(uv_loop_t* loop) {
loop->cf_state = NULL;
@ -48,15 +53,19 @@ void uv__platform_loop_delete(uv_loop_t* loop) {
}
uint64_t uv__hrtime(uv_clocktype_t type) {
static mach_timebase_info_data_t info;
if ((ACCESS_ONCE(uint32_t, info.numer) == 0 ||
ACCESS_ONCE(uint32_t, info.denom) == 0) &&
mach_timebase_info(&info) != KERN_SUCCESS)
static void uv__hrtime_init_once(void) {
if (KERN_SUCCESS != mach_timebase_info(&timebase))
abort();
return mach_absolute_time() * info.numer / info.denom;
time_func = (uint64_t (*)(void)) dlsym(RTLD_DEFAULT, "mach_continuous_time");
if (time_func == NULL)
time_func = mach_absolute_time;
}
uint64_t uv__hrtime(uv_clocktype_t type) {
uv_once(&once, uv__hrtime_init_once);
return time_func() * timebase.numer / timebase.denom;
}