Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(1128)

Unified Diff: tools/timer/SysTimer_windows.cpp

Issue 1420923003: Revert of SkTime::GetNSecs() (Closed) Base URL: https://skia.googlesource.com/skia.git@master
Patch Set: Created 5 years, 2 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « tools/timer/SysTimer_windows.h ('k') | tools/timer/Timer.h » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: tools/timer/SysTimer_windows.cpp
diff --git a/tools/timer/SysTimer_windows.cpp b/tools/timer/SysTimer_windows.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..8e45b4a68ed3ccabab401ec27f6138e490e56d22
--- /dev/null
+++ b/tools/timer/SysTimer_windows.cpp
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SysTimer_windows.h"
+
+#include <intrin.h>
+
+static ULONGLONG win_cpu_time() {
+ FILETIME createTime;
+ FILETIME exitTime;
+ FILETIME usrTime;
+ FILETIME sysTime;
+ if (0 == GetProcessTimes(GetCurrentProcess(), &createTime, &exitTime, &sysTime, &usrTime)) {
+ return 0;
+ }
+ ULARGE_INTEGER start_cpu_sys;
+ ULARGE_INTEGER start_cpu_usr;
+ start_cpu_sys.LowPart = sysTime.dwLowDateTime;
+ start_cpu_sys.HighPart = sysTime.dwHighDateTime;
+ start_cpu_usr.LowPart = usrTime.dwLowDateTime;
+ start_cpu_usr.HighPart = usrTime.dwHighDateTime;
+ return start_cpu_sys.QuadPart + start_cpu_usr.QuadPart;
+}
+
+void SysTimer::startCpu() {
+ fStartCpu = win_cpu_time();
+}
+
+double SysTimer::endCpu() {
+ ULONGLONG end_cpu = win_cpu_time();
+ return static_cast<double>(end_cpu - fStartCpu) / 10000.0L;
+}
+
+// On recent Intel chips (roughly, "has Core or Atom in its name") __rdtsc will always tick
+// at the CPU's maximum rate, even while power management clocks the CPU up and down.
+// That's great, because it makes measuring wall time super simple.
+
+void SysTimer::startWall() {
+ fStartWall = __rdtsc();
+}
+
+double SysTimer::endWall() {
+ unsigned __int64 end = __rdtsc();
+
+ // This seems to, weirdly, give the CPU frequency in kHz. That's exactly what we want!
+ LARGE_INTEGER freq_khz;
+ QueryPerformanceFrequency(&freq_khz);
+
+ return static_cast<double>(end - fStartWall) / static_cast<double>(freq_khz.QuadPart);
+}
« no previous file with comments | « tools/timer/SysTimer_windows.h ('k') | tools/timer/Timer.h » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698