Merge pull request #2293 from stephentoub/tickcount_perf

Use CLOCK_MONOTONIC_COARSE in GetTickCount64

3 files changed, 23 insertions, 3 deletions

diff --git a/src/pal/src/config.h.in b/src/pal/src/config.h.in
index 143679d5a7..672cfe1d31 100644
--- a/src/pal/src/config.h.in
+++ b/src/pal/src/config.h.in
@@ -82,6 +82,7 @@
 #cmakedefine01 HAVE_WORKING_GETTIMEOFDAY
 #cmakedefine01 HAVE_WORKING_CLOCK_GETTIME
 #cmakedefine01 HAVE_CLOCK_MONOTONIC
+#cmakedefine01 HAVE_CLOCK_MONOTONIC_COARSE
 #cmakedefine01 HAVE_MACH_ABSOLUTE_TIME
 #cmakedefine01 HAVE_CLOCK_THREAD_CPUTIME
 #cmakedefine01 STATVFS64_PROTOTYPE_BROKEN
diff --git a/src/pal/src/configure.cmake b/src/pal/src/configure.cmake
index 333f0094c5..d130e14123 100644
--- a/src/pal/src/configure.cmake
+++ b/src/pal/src/configure.cmake
@@ -343,6 +343,19 @@ int main()
 }" HAVE_CLOCK_MONOTONIC)
 check_cxx_source_runs("
 #include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+
+int main()
+{
+  int ret;
+  struct timespec ts;
+  ret = clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);
+
+  exit(ret);
+}" HAVE_CLOCK_MONOTONIC_COARSE)
+check_cxx_source_runs("
+#include <stdlib.h>
 #include <mach/mach_time.h>
 
 int main()
diff --git a/src/pal/src/misc/time.cpp b/src/pal/src/misc/time.cpp
index 2f20c60914..939c86996a 100644
--- a/src/pal/src/misc/time.cpp
+++ b/src/pal/src/misc/time.cpp
@@ -337,12 +337,18 @@ GetTickCount64()
 {
     ULONGLONG retval = 0;
 
-#if HAVE_CLOCK_MONOTONIC
+#if HAVE_CLOCK_MONOTONIC_COARSE || HAVE_CLOCK_MONOTONIC
     {
+        clockid_t clockType = 
+#if HAVE_CLOCK_MONOTONIC_COARSE
+            CLOCK_MONOTONIC_COARSE; // good enough resolution, fastest speed
+#else
+            CLOCK_MONOTONIC;
+#endif
         struct timespec ts;
-        if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
+        if (clock_gettime(clockType, &ts) != 0)
         {
-            ASSERT("clock_gettime(CLOCK_MONOTONIC) failed; errno is %d (%s)\n", errno, strerror(errno));
+            ASSERT("clock_gettime(CLOCK_MONOTONIC*) failed; errno is %d (%s)\n", errno, strerror(errno));
             goto EXIT;
         }
         retval = (ts.tv_sec * tccSecondsToMillieSeconds)+(ts.tv_nsec / tccMillieSecondsToNanoSeconds);