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fix: intermittent 100% CPU usage on macOS
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codebytere committed Jul 4, 2020
1 parent 6dd394a commit 3902de2
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1 change: 1 addition & 0 deletions patches/node/.patches
Expand Up @@ -40,3 +40,4 @@ fix_don_t_preparemainexecution_twice.patch
win_use_rtlgenrandom_from_advapi32_dll_directly.patch
tools_update_certdata_txt.patch
crypto_update_root_certificates.patch
darwin_work_around_clock_jumping_back_in_time.patch
64 changes: 64 additions & 0 deletions patches/node/darwin_work_around_clock_jumping_back_in_time.patch
@@ -0,0 +1,64 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Wed, 1 Jul 2020 10:32:57 +0200
Subject: darwin: work around clock jumping back in time

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>

diff --git a/deps/uv/src/unix/darwin.c b/deps/uv/src/unix/darwin.c
index 5cf03aea0b405402b88494f3840bcfe606551b53..030ed1adb23966f89877135dd0bd20629248f007 100644
--- a/deps/uv/src/unix/darwin.c
+++ b/deps/uv/src/unix/darwin.c
@@ -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;
}


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