zend_hrtime: check posix clock once and prefer CLOCK_MONOTONIC_RAW

Author: marc-mabe

Zend/zend_hrtime.c

@@ -27,6 +27,8 @@
 # include <time.h>
 # include <string.h>
 
+ZEND_API clockid_t zend_hrtime_posix_clock_id = CLOCK_MONOTONIC;
+
 #elif ZEND_HRTIME_PLATFORM_WINDOWS
 
 # define WIN32_LEAN_AND_MEAN
@@ -66,5 +68,22 @@ void zend_startup_hrtime(void)
 
 	mach_timebase_info(&zend_hrtime_timerlib_info);
 
+#elif ZEND_HRTIME_PLATFORM_POSIX
+
+	struct timespec ts;
+
+#ifdef CLOCK_MONOTONIC_RAW
+	if (EXPECTED(0 == clock_gettime(CLOCK_MONOTONIC_RAW, &ts))) {
+		zend_hrtime_posix_clock_id = CLOCK_MONOTONIC_RAW;
+		return;
+	}
+#endif
+
+	if (EXPECTED(0 == clock_gettime(zend_hrtime_posix_clock_id, &ts))) {
+		return;
+	}
+
+	ZEND_ASSERT(0 && "No working CLOCK_MONOTONIC* found, this should never happen");
+
 #endif
 }

Zend/zend_hrtime.h

@@ -72,6 +72,10 @@ ZEND_API extern double zend_hrtime_timer_scale;
 # include <string.h>
 ZEND_API extern mach_timebase_info_data_t zend_hrtime_timerlib_info;
 
+#elif ZEND_HRTIME_PLATFORM_POSIX
+
+ZEND_API extern clockid_t zend_hrtime_posix_clock_id;
+
 #endif
 
 #define ZEND_NANO_IN_SEC UINT64_C(1000000000)
@@ -92,10 +96,8 @@ static zend_always_inline zend_hrtime_t zend_hrtime(void)
 	return (zend_hrtime_t)mach_absolute_time() * zend_hrtime_timerlib_info.numer / zend_hrtime_timerlib_info.denom;
 #elif ZEND_HRTIME_PLATFORM_POSIX
 	struct timespec ts = { .tv_sec = 0, .tv_nsec = 0 };
-	if (EXPECTED(0 == clock_gettime(CLOCK_MONOTONIC, &ts))) {
-		return ((zend_hrtime_t) ts.tv_sec * (zend_hrtime_t)ZEND_NANO_IN_SEC) + ts.tv_nsec;
-	}
-	return 0;
+	clock_gettime(zend_hrtime_posix_clock_id, &ts);
+	return ((zend_hrtime_t) ts.tv_sec * (zend_hrtime_t)ZEND_NANO_IN_SEC) + ts.tv_nsec;
 #elif ZEND_HRTIME_PLATFORM_HPUX
 	return (zend_hrtime_t) gethrtime();
 #elif  ZEND_HRTIME_PLATFORM_AIX