Revert of SkTime::GetNSecs() (patchset #10 id:180001 of https://codereview.chromium.org/1422513003/ )

Reason for revert:
https://codereview.chromium.org/1412453006

Original issue's description:
> SkTime::GetNSecs()
>
>    - Move high-precision wall timers from tools/timer to SkTime.
>    - Implement SkTime::GetMSecs() in terms of SkTime::GetNSecs().
>    - Delete unused tools/timer code.
>
> I have no idea what's going on there in src/animator.
> I don't intend to investigate.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/70084cbc16ee8162649f2601377feb6e49de0217
>
> CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Debug-CrOS_Link-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/a1840d50e29fd95e4df2d1168fe54c34c2a5c30c

TBR=caryclark@google.com,reed@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1417753003

gyp/core.gyp

@@ -40,7 +40,6 @@
         [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "chromeos"]', {
           'link_settings': {
             'libraries': [
-              '-lrt',
               '-lpthread',
             ],
           },

gyp/tools.gyp

@@ -132,11 +132,39 @@
     {
       'target_name' : 'timer',
       'type': 'static_library',
-      'sources': [ '../tools/timer/Timer.cpp' ],
+      'sources': [
+        '../tools/timer/Timer.cpp',
+        '../tools/timer/TimerData.cpp',
+      ],
+      'include_dirs': [
+        '../include/private',
+        '../src/core',
+        '../src/gpu',
+      ],
       'direct_dependent_settings': {
         'include_dirs': ['../tools/timer'],
       },
-      'dependencies': [ 'skia_lib.gyp:skia_lib' ],
+      'dependencies': [
+        'skia_lib.gyp:skia_lib',
+        'jsoncpp.gyp:jsoncpp',
+      ],
+      'conditions': [
+        ['skia_gpu == 1', {
+          'sources': [ '../tools/timer/GpuTimer.cpp' ],
+        }],
+        [ 'skia_os in ["mac", "ios"]', {
+          'sources': [ '../tools/timer/SysTimer_mach.cpp' ],
+        }],
+        [ 'skia_os == "win"', {
+          'sources': [ '../tools/timer/SysTimer_windows.cpp' ],
+        }],
+        [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "android", "chromeos"]', {
+          'sources': [ '../tools/timer/SysTimer_posix.cpp' ],
+        }],
+        [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "chromeos"]', {
+          'link_settings': { 'libraries': [ '-lrt' ] },
+        }],
+      ],
     },
     {
       'target_name': 'skdiff',

include/core/SkTime.h

@@ -34,8 +34,7 @@ public:
     };
     static void GetDateTime(DateTime*);
 
-    static SkMSec GetMSecs() { return (SkMSec)(GetNSecs() * 1e-6); }
-    static double GetNSecs();
+    static SkMSec GetMSecs();
 };
 
 #if defined(SK_DEBUG) && defined(SK_BUILD_FOR_WIN32)

src/animator/SkTime.cpp

@@ -28,6 +28,15 @@ void SkTime::GetDateTime(DateTime* t) {
     }
 }
 
+SkMSec SkTime::GetMSecs() {
+#ifdef SK_DEBUG
+    if (gForceTickCount != (SkMSec) -1) {
+        return gForceTickCount;
+    }
+#endif
+    return ::GetTickCount();
+}
+
 #elif defined(xSK_BUILD_FOR_MAC)
 
 #include <time.h>
@@ -49,4 +58,13 @@ void SkTime::GetDateTime(DateTime* t) {
     }
 }
 
+SkMSec SkTime::GetMSecs() {
+    UnsignedWide    wide;
+    ::Microseconds(&wide);
+
+    int64_t s = ((int64_t)wide.hi << 32) | wide.lo;
+    s = (s + 500) / 1000;   // rounded divide
+    return (SkMSec)s;
+}
+
 #endif

src/core/SkTime.cpp

@@ -5,7 +5,6 @@
  * found in the LICENSE file.
  */
 
-#include "SkOncePtr.h"
 #include "SkString.h"
 #include "SkTime.h"
 
@@ -23,37 +22,3 @@ void SkTime::DateTime::toISO8601(SkString* dst) const {
                     timeZoneMinutes);
     }
 }
-
-// TODO: use rdtscp when (runtime) available
-// TODO: use std::chrono when (compile-time) available
-
-#if defined(_MSC_VER)
-    #include <intrin.h>
-    SK_DECLARE_STATIC_ONCE_PTR(double, ns_per_tick);
-    double SkTime::GetNSecs() {
-        uint64_t ticks = __rdtsc();
-        return ticks * *ns_per_tick.get([]{
-            LARGE_INTEGER khz;  // The docs say this returns Hz, but it returns KHz.
-            QueryPerformanceFrequency(&khz);
-            return new double(1e6 / khz.QuadPart);
-        });
-    }
-#elif defined(__MACH__)
-    #include <mach/mach_time.h>
-    SK_DECLARE_STATIC_ONCE_PTR(double, ns_per_tick);
-    double SkTime::GetNSecs() {
-        uint64_t ticks = mach_absolute_time();
-        return ticks * *ns_per_tick.get([]{
-            mach_timebase_info_data_t timebase;
-            (void)mach_timebase_info(&timebase);
-            return new double(timebase.numer * 1.0 / timebase.denom);
-        });
-    }
-#else
-    #include <time.h>
-    double SkTime::GetNSecs() {
-        struct timespec ts = {0, 0};
-        (void)clock_gettime(CLOCK_MONOTONIC, &ts);
-        return ts.tv_sec * 1e9 + ts.tv_nsec;
-    }
-#endif

src/ports/SkTime_Unix.cpp

@@ -34,3 +34,10 @@ void SkTime::GetDateTime(DateTime* dt)
         dt->fSecond     = SkToU8(tstruct->tm_sec);
     }
 }
+
+SkMSec SkTime::GetMSecs()
+{
+    struct timeval tv;
+    gettimeofday(&tv, nullptr);
+    return (SkMSec) (tv.tv_sec * 1000 + tv.tv_usec / 1000 ); // microseconds to milliseconds
+}

src/ports/SkTime_win.cpp

@@ -39,3 +39,14 @@ void SkTime::GetDateTime(DateTime* dt)
         dt->fSecond     = SkToU8(st.wSecond);
     }
 }
+
+SkMSec SkTime::GetMSecs()
+{
+    FILETIME        ft;
+    LARGE_INTEGER   li;
+    GetSystemTimeAsFileTime(&ft);
+    li.LowPart  = ft.dwLowDateTime;
+    li.HighPart = ft.dwHighDateTime;
+    __int64 t  = li.QuadPart;       /* In 100-nanosecond intervals */
+    return (SkMSec)(t / 10000);               /* In milliseconds */
+}

tools/timer/GpuTimer.cpp

@@ -0,0 +1,77 @@
+
+/*
+ * 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 "GpuTimer.h"
+#include "gl/SkGLContext.h"
+#include "gl/GrGLUtil.h"
+
+GpuTimer::GpuTimer(const SkGLContext* glctx) : fContext(glctx) {
+    if (fContext) {
+        fContext->ref();
+        fContext->makeCurrent();
+        fStarted = false;
+        fSupported = GrGLGetVersion(fContext->gl()) > GR_GL_VER(3,3) ||
+                fContext->gl()->hasExtension("GL_ARB_timer_query") ||
+                fContext->gl()->hasExtension("GL_EXT_timer_query");
+
+        if (fSupported) {
+            SK_GL(*fContext, GenQueries(1, &fQuery));
+        }
+    }
+}
+
+GpuTimer::~GpuTimer() {
+    if (fContext) {
+        if (fSupported) {
+            fContext->makeCurrent();
+            SK_GL(*fContext, DeleteQueries(1, &fQuery));
+        }
+        fContext->unref();
+    }
+}
+
+void GpuTimer::start() {
+    if (fContext && fSupported) {
+        fContext->makeCurrent();
+        fStarted = true;
+        SK_GL(*fContext, BeginQuery(GR_GL_TIME_ELAPSED, fQuery));
+    }
+}
+
+/**
+ * It is important to stop the cpu clocks first,
+ * as this will cpu wait for the gpu to finish.
+ */
+double GpuTimer::end() {
+    if (fContext && fSupported) {
+        fStarted = false;
+        fContext->makeCurrent();
+        SK_GL(*fContext, EndQuery(GR_GL_TIME_ELAPSED));
+
+        GrGLint available = 0;
+        while (!available) {
+            SK_GL_NOERRCHECK(*fContext, GetQueryObjectiv(fQuery,
+                                                         GR_GL_QUERY_RESULT_AVAILABLE,
+                                                         &available));
+            // If GetQueryObjectiv is erroring out we need some alternative
+            // means of breaking out of this loop
+            GrGLenum error;
+            SK_GL_RET_NOERRCHECK(*fContext, error, GetError());
+            if (GR_GL_NO_ERROR != error) {
+                break;
+            }
+        }
+        GrGLuint64 totalGPUTimeElapsed = 0;
+        SK_GL(*fContext, GetQueryObjectui64v(fQuery,
+                                             GR_GL_QUERY_RESULT,
+                                             &totalGPUTimeElapsed));
+
+        return totalGPUTimeElapsed / 1000000.0;
+    } else {
+        return 0;
+    }
+}

tools/timer/GpuTimer.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef GpuTimer_DEFINED
+#define GpuTimer_DEFINED
+
+class SkGLContext;
+
+class GpuTimer {
+public:
+    GpuTimer(const SkGLContext*);
+    ~GpuTimer();
+    void start();
+    double end();
+private:
+    unsigned fQuery;
+    int fStarted;
+    const SkGLContext* fContext;
+    bool fSupported;
+};
+
+#endif

tools/timer/SysTimer_mach.cpp

@@ -0,0 +1,66 @@
+/*
+ * 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_mach.h"
+
+static time_value_t mac_cpu_time() {
+    mach_port_t task = mach_task_self();
+    if (task == MACH_PORT_NULL) {
+        time_value_t none = {0, 0};
+        return none;
+    }
+
+    task_thread_times_info thread_info_data;
+    mach_msg_type_number_t thread_info_count = TASK_THREAD_TIMES_INFO_COUNT;
+    if (KERN_SUCCESS != task_info(task,
+                                  TASK_THREAD_TIMES_INFO,
+                                  reinterpret_cast<task_info_t>(&thread_info_data),
+                                  &thread_info_count)) {
+        time_value_t none = {0, 0};
+        return none;
+    }
+
+    time_value_add(&thread_info_data.user_time, &thread_info_data.system_time)
+    return thread_info_data.user_time;
+}
+
+static double interval_in_ms(time_value_t start_clock, time_value_t end_clock) {
+    double duration_clock;
+    if ((end_clock.microseconds - start_clock.microseconds) < 0) {
+        duration_clock = (end_clock.seconds - start_clock.seconds-1) * 1000;
+        duration_clock += (1000000 + end_clock.microseconds - start_clock.microseconds) / 1000.0;
+    } else {
+        duration_clock = (end_clock.seconds - start_clock.seconds) * 1000;
+        duration_clock += (end_clock.microseconds - start_clock.microseconds) / 1000.0;
+    }
+    return duration_clock;
+}
+
+void SysTimer::startWall() {
+    fStartWall = mach_absolute_time();
+}
+
+void SysTimer::startCpu() {
+    fStartCpu = mac_cpu_time();
+}
+
+double SysTimer::endCpu() {
+    time_value_t end_cpu = mac_cpu_time();
+    return interval_in_ms(fStartCpu, end_cpu);
+}
+
+double SysTimer::endWall() {
+    uint64_t end_wall = mach_absolute_time();
+
+    uint64_t elapsed = end_wall - fStartWall;
+    mach_timebase_info_data_t sTimebaseInfo;
+    if (KERN_SUCCESS != mach_timebase_info(&sTimebaseInfo)) {
+        return 0;
+    } else {
+        uint64_t elapsedNano = elapsed * sTimebaseInfo.numer / sTimebaseInfo.denom;
+        return elapsedNano / 1000000.0;
+    }
+}

tools/timer/SysTimer_mach.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SysTimer_DEFINED
+#define SysTimer_DEFINED
+
+#include <mach/mach.h>
+#include <mach/mach_time.h>
+
+class SysTimer {
+public:
+    void startWall();
+    void startCpu();
+    double endCpu();
+    double endWall();
+private:
+    time_value_t fStartCpu;
+    uint64_t fStartWall;
+};
+
+#endif

tools/timer/SysTimer_posix.cpp

@@ -0,0 +1,51 @@
+/*
+ * 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_posix.h"
+
+static double interval_in_ms(timespec start_clock, timespec end_clock)
+{
+    double duration_clock;
+    if ((end_clock.tv_nsec - start_clock.tv_nsec) < 0) {
+        duration_clock = (end_clock.tv_sec - start_clock.tv_sec - 1) * 1000;
+        duration_clock += (1000000000 + end_clock.tv_nsec - start_clock.tv_nsec) / 1000000.0;
+    } else {
+        duration_clock = (end_clock.tv_sec - start_clock.tv_sec) * 1000;
+        duration_clock += (end_clock.tv_nsec - start_clock.tv_nsec) / 1000000.0;
+    }
+    return duration_clock;
+}
+
+void SysTimer::startWall() {
+    if (-1 == clock_gettime(CLOCK_MONOTONIC, &fWall)) {
+        timespec none = {0, 0};
+        fWall = none;
+    }
+}
+void SysTimer::startCpu() {
+    if (-1 == clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &fCpu)) {
+        timespec none = {0, 0};
+        fCpu = none;
+    }
+}
+
+double SysTimer::endCpu() {
+    timespec end_cpu;
+    if (-1 == clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end_cpu)) {
+        timespec none = {0, 0};
+        end_cpu = none;
+    }
+    return interval_in_ms(fCpu, end_cpu);
+}
+
+double SysTimer::endWall() {
+    timespec end_wall;
+    if (-1 == clock_gettime(CLOCK_MONOTONIC, &end_wall)) {
+        timespec none = {0, 0};
+        end_wall = none;
+    }
+    return interval_in_ms(fWall, end_wall);
+}

tools/timer/SysTimer_posix.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SysTimer_DEFINED
+#define SysTimer_DEFINED
+
+#include <time.h>
+
+class SysTimer {
+public:
+    void startWall();
+    void startCpu();
+    double endCpu();
+    double endWall();
+private:
+    timespec fCpu;
+    timespec fWall;
+};
+
+#endif

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);
+}

tools/timer/SysTimer_windows.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SysTimer_DEFINED
+#define SysTimer_DEFINED
+
+//Time
+#define WIN32_LEAN_AND_MEAN 1
+#include <windows.h>
+
+class SysTimer {
+public:
+    void startWall();
+    void startCpu();
+    double endCpu();
+    double endWall();
+private:
+    ULONGLONG fStartCpu;
+    unsigned __int64 fStartWall;
+};
+
+#endif

tools/timer/Timer.cpp

@@ -6,6 +6,52 @@
  */
 #include "Timer.h"
 
+Timer::Timer(SkGLContext* gl)
+        : fCpu(-1.0)
+        , fWall(-1.0)
+        , fTruncatedCpu(-1.0)
+        , fTruncatedWall(-1.0)
+        , fGpu(-1.0)
+#if SK_SUPPORT_GPU
+        , fGpuTimer(gl)
+#endif
+        {}
+
+void Timer::start() {
+    fSysTimer.startWall();
+    fTruncatedSysTimer.startWall();
+#if SK_SUPPORT_GPU
+    fGpuTimer.start();
+#endif
+    fSysTimer.startCpu();
+    fTruncatedSysTimer.startCpu();
+}
+
+void Timer::end() {
+    fCpu = fSysTimer.endCpu();
+#if SK_SUPPORT_GPU
+    //It is important to stop the cpu clocks first,
+    //as the following will cpu wait for the gpu to finish.
+    fGpu = fGpuTimer.end();
+#endif
+    fWall = fSysTimer.endWall();
+}
+
+void Timer::truncatedEnd() {
+    fTruncatedCpu = fTruncatedSysTimer.endCpu();
+    fTruncatedWall = fTruncatedSysTimer.endWall();
+}
+
+WallTimer::WallTimer() : fWall(-1.0) {}
+
+void WallTimer::start() {
+    fSysTimer.startWall();
+}
+
+void WallTimer::end() {
+    fWall = fSysTimer.endWall();
+}
+
 SkString HumanizeMs(double ms) {
     if (ms > 60e+3)  return SkStringPrintf("%.3gm", ms/60e+3);
     if (ms >  1e+3)  return SkStringPrintf("%.3gs",  ms/1e+3);

tools/timer/Timer.h

@@ -7,18 +7,68 @@
 #ifndef Timer_DEFINED
 #define Timer_DEFINED
 
-#include "SkString.h"
-#include "SkTime.h"
 #include "SkTypes.h"
+#include "SkString.h"
 
+#if defined(SK_BUILD_FOR_WIN32)
+    #include "SysTimer_windows.h"
+#elif defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
+    #include "SysTimer_mach.h"
+#elif defined(SK_BUILD_FOR_UNIX) || defined(SK_BUILD_FOR_ANDROID)
+    #include "SysTimer_posix.h"
+#endif
+
+#if SK_SUPPORT_GPU
+    #include "GpuTimer.h"
+#endif
+
+class SkGLContext;
+
+/**
+ * SysTimers and GpuTimers are implemented orthogonally.
+ * This class combines 2 SysTimers and a GpuTimer into one single,
+ * platform specific Timer with a simple interface. The truncated
+ * timer doesn't include the time required for the GPU to finish
+ * its rendering. It should always be <= the un-truncated system
+ * times and (for GPU configurations) can be used to roughly (very
+ * roughly) gauge the GPU load/backlog.
+ */
+class Timer {
+public:
+    explicit Timer(SkGLContext* gl = nullptr);
+
+    void start();
+    void truncatedEnd();
+    void end();
+
+    // All times in milliseconds.
+    double fCpu;
+    double fWall;
+    double fTruncatedCpu;
+    double fTruncatedWall;
+    double fGpu;
+
+private:
+    SysTimer fSysTimer;
+    SysTimer fTruncatedSysTimer;
+#if SK_SUPPORT_GPU
+    GpuTimer fGpuTimer;
+#endif
+};
+
+// Same as Timer above, supporting only fWall but with much lower overhead.
+// (Typically, ~30ns instead of Timer's ~1us.)
 class WallTimer {
 public:
-    WallTimer() : fWall(-1) {}
+    WallTimer();
 
-    void start() { fWall = SkTime::GetNSecs(); }
-    void end()   { fWall = (SkTime::GetNSecs() - fWall) * 1e-6; }
+    void start();
+    void end();
 
     double fWall;  // Milliseconds.
+
+private:
+    SysTimer fSysTimer;
 };
 
 SkString HumanizeMs(double);

tools/timer/TimerData.cpp

@@ -0,0 +1,220 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "TimerData.h"
+
+#include "Timer.h"
+#include <limits>
+
+TimerData::TimerData(int maxNumTimings)
+    : fMaxNumTimings(maxNumTimings)
+    , fCurrTiming(0)
+    , fWallTimes(maxNumTimings)
+    , fTruncatedWallTimes(maxNumTimings)
+    , fCpuTimes(maxNumTimings)
+    , fTruncatedCpuTimes(maxNumTimings)
+    , fGpuTimes(maxNumTimings) {}
+
+bool TimerData::appendTimes(Timer* timer) {
+    SkASSERT(timer != nullptr);
+    if (fCurrTiming >= fMaxNumTimings) {
+        return false;
+    }
+
+    fWallTimes[fCurrTiming] = timer->fWall;
+    fTruncatedWallTimes[fCurrTiming] = timer->fTruncatedWall;
+    fCpuTimes[fCurrTiming] = timer->fCpu;
+    fTruncatedCpuTimes[fCurrTiming] = timer->fTruncatedCpu;
+    fGpuTimes[fCurrTiming] = timer->fGpu;
+
+    ++fCurrTiming;
+
+    return true;
+}
+
+SkString TimerData::getResult(const char* doubleFormat,
+                              Result result,
+                              const char *configName,
+                              uint32_t timerFlags,
+                              int itersPerTiming) {
+    SkASSERT(itersPerTiming >= 1);
+
+    if (!fCurrTiming) {
+        return SkString("");
+    }
+
+    int numTimings = fCurrTiming;
+
+    SkString wallStr(" msecs = ");
+    SkString truncWallStr(" Wmsecs = ");
+    SkString cpuStr(" cmsecs = ");
+    SkString truncCpuStr(" Cmsecs = ");
+    SkString gpuStr(" gmsecs = ");
+
+    double wallMin = std::numeric_limits<double>::max();
+    double truncWallMin = std::numeric_limits<double>::max();
+    double cpuMin = std::numeric_limits<double>::max();
+    double truncCpuMin = std::numeric_limits<double>::max();
+    double gpuMin = std::numeric_limits<double>::max();
+
+    double wallSum = 0;
+    double truncWallSum = 0;
+    double cpuSum = 0;
+    double truncCpuSum = 0;
+    double gpuSum = 0;
+
+    for (int i = 0; i < numTimings; ++i) {
+        if (kPerIter_Result == result) {
+            wallStr.appendf(doubleFormat, fWallTimes[i] / itersPerTiming);
+            truncWallStr.appendf(doubleFormat, fTruncatedWallTimes[i] / itersPerTiming);
+            cpuStr.appendf(doubleFormat, fCpuTimes[i] / itersPerTiming);
+            truncCpuStr.appendf(doubleFormat, fTruncatedCpuTimes[i] / itersPerTiming);
+            gpuStr.appendf(doubleFormat, fGpuTimes[i] / itersPerTiming);
+
+            if (i != numTimings - 1) {
+                static const char kSep[] = ", ";
+                wallStr.append(kSep);
+                truncWallStr.append(kSep);
+                cpuStr.append(kSep);
+                truncCpuStr.append(kSep);
+                gpuStr.append(kSep);
+            }
+        } else if (kMin_Result == result) {
+            wallMin = SkTMin(wallMin, fWallTimes[i]);
+            truncWallMin = SkTMin(truncWallMin, fTruncatedWallTimes[i]);
+            cpuMin = SkTMin(cpuMin, fCpuTimes[i]);
+            truncCpuMin = SkTMin(truncCpuMin, fTruncatedCpuTimes[i]);
+            gpuMin = SkTMin(gpuMin, fGpuTimes[i]);
+        } else {
+            SkASSERT(kAvg_Result == result);
+            wallSum += fWallTimes[i];
+            truncWallSum += fTruncatedWallTimes[i];
+            cpuSum += fCpuTimes[i];
+            truncCpuSum += fTruncatedCpuTimes[i];
+        }
+
+        // We always track the GPU sum because whether it is non-zero indicates if valid gpu times
+        // were recorded at all.
+        gpuSum += fGpuTimes[i];
+    }
+
+    if (kMin_Result == result) {
+        wallStr.appendf(doubleFormat, wallMin / itersPerTiming);
+        truncWallStr.appendf(doubleFormat, truncWallMin / itersPerTiming);
+        cpuStr.appendf(doubleFormat, cpuMin / itersPerTiming);
+        truncCpuStr.appendf(doubleFormat, truncCpuMin / itersPerTiming);
+        gpuStr.appendf(doubleFormat, gpuMin / itersPerTiming);
+    } else if (kAvg_Result == result) {
+        int divisor = numTimings * itersPerTiming;
+        wallStr.appendf(doubleFormat, wallSum / divisor);
+        truncWallStr.appendf(doubleFormat, truncWallSum / divisor);
+        cpuStr.appendf(doubleFormat, cpuSum / divisor);
+        truncCpuStr.appendf(doubleFormat, truncCpuSum / divisor);
+        gpuStr.appendf(doubleFormat, gpuSum / divisor);
+    }
+
+    SkString str;
+    str.printf("  %4s:", configName);
+    if (timerFlags & kWall_Flag) {
+        str += wallStr;
+    }
+    if (timerFlags & kTruncatedWall_Flag) {
+        str += truncWallStr;
+    }
+    if (timerFlags & kCpu_Flag) {
+        str += cpuStr;
+    }
+    if (timerFlags & kTruncatedCpu_Flag) {
+        str += truncCpuStr;
+    }
+    if ((timerFlags & kGpu_Flag) && gpuSum > 0) {
+        str += gpuStr;
+    }
+    return str;
+}
+
+Json::Value TimerData::getJSON(uint32_t timerFlags,
+                               Result result,
+                               int itersPerTiming) {
+    SkASSERT(itersPerTiming >= 1);
+    Json::Value dataNode;
+    Json::Value wallNode, truncWall, cpuNode, truncCpu, gpuNode;
+    if (!fCurrTiming) {
+        return dataNode;
+    }
+
+    int numTimings = fCurrTiming;
+
+    double wallMin = std::numeric_limits<double>::max();
+    double truncWallMin = std::numeric_limits<double>::max();
+    double cpuMin = std::numeric_limits<double>::max();
+    double truncCpuMin = std::numeric_limits<double>::max();
+    double gpuMin = std::numeric_limits<double>::max();
+
+    double wallSum = 0;
+    double truncWallSum = 0;
+    double cpuSum = 0;
+    double truncCpuSum = 0;
+    double gpuSum = 0;
+
+    for (int i = 0; i < numTimings; ++i) {
+        if (kPerIter_Result == result) {
+            wallNode.append(fWallTimes[i] / itersPerTiming);
+            truncWall.append(fTruncatedWallTimes[i] / itersPerTiming);
+            cpuNode.append(fCpuTimes[i] / itersPerTiming);
+            truncCpu.append(fTruncatedCpuTimes[i] / itersPerTiming);
+            gpuNode.append(fGpuTimes[i] / itersPerTiming);
+        } else if (kMin_Result == result) {
+            wallMin = SkTMin(wallMin, fWallTimes[i]);
+            truncWallMin = SkTMin(truncWallMin, fTruncatedWallTimes[i]);
+            cpuMin = SkTMin(cpuMin, fCpuTimes[i]);
+            truncCpuMin = SkTMin(truncCpuMin, fTruncatedCpuTimes[i]);
+            gpuMin = SkTMin(gpuMin, fGpuTimes[i]);
+        } else {
+            SkASSERT(kAvg_Result == result);
+            wallSum += fWallTimes[i];
+            truncWallSum += fTruncatedWallTimes[i];
+            cpuSum += fCpuTimes[i];
+            truncCpuSum += fTruncatedCpuTimes[i];
+        }
+
+        // We always track the GPU sum because whether it is non-zero indicates if valid gpu times
+        // were recorded at all.
+        gpuSum += fGpuTimes[i];
+    }
+
+    if (kMin_Result == result) {
+        wallNode.append(wallMin / itersPerTiming);
+        truncWall.append(truncWallMin / itersPerTiming);
+        cpuNode.append(cpuMin / itersPerTiming);
+        truncCpu.append(truncCpuMin / itersPerTiming);
+        gpuNode.append(gpuMin / itersPerTiming);
+    } else if (kAvg_Result == result) {
+        int divisor = numTimings * itersPerTiming;
+        wallNode.append(wallSum / divisor);
+        truncWall.append(truncWallSum / divisor);
+        cpuNode.append(cpuSum / divisor);
+        truncCpu.append(truncCpuSum / divisor);
+        gpuNode.append(gpuSum / divisor);
+    }
+
+    if (timerFlags & kWall_Flag) {
+        dataNode["wall"] = wallNode;
+    }
+    if (timerFlags & kTruncatedWall_Flag) {
+        dataNode["truncWall"] = truncWall;
+    }
+    if (timerFlags & kCpu_Flag) {
+        dataNode["cpu"] = cpuNode;
+    }
+    if (timerFlags & kTruncatedCpu_Flag) {
+        dataNode["trucCpu"] = truncCpu;
+    }
+    if ((timerFlags & kGpu_Flag) && gpuSum > 0) {
+        dataNode["gpu"] = gpuNode;
+    }
+    return dataNode;
+}

tools/timer/TimerData.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef TimerData_DEFINED
+#define TimerData_DEFINED
+
+#include "SkString.h"
+#include "SkTemplates.h"
+
+#ifdef SK_BUILD_FOR_WIN
+    #pragma warning(push)
+    #pragma warning(disable : 4530)
+#endif
+
+#include "SkJSONCPP.h"
+
+#ifdef SK_BUILD_FOR_WIN
+    #pragma warning(pop)
+#endif
+
+class Timer;
+
+class TimerData {
+public:
+    /**
+     * Constructs a TimerData to hold at most maxNumTimings sets of elapsed timer values.
+     **/
+    explicit TimerData(int maxNumTimings);
+
+    /**
+     * Collect times from the Timer for an iteration. It will fail if called more often than
+     * indicated in the constructor.
+     *
+     * @param Timer Must not be null.
+     */
+    bool appendTimes(Timer*);
+
+    enum Result {
+        kMin_Result,
+        kAvg_Result,
+        kPerIter_Result
+    };
+
+    enum TimerFlags {
+        kWall_Flag              = 0x1,
+        kTruncatedWall_Flag     = 0x2,
+        kCpu_Flag               = 0x4,
+        kTruncatedCpu_Flag      = 0x8,
+        kGpu_Flag               = 0x10
+    };
+
+    /**
+     * Gets the timer data results as a string.
+     * @param doubleFormat printf-style format for doubles (e.g. "%02d")
+     * @param result the type of result desired
+     * @param the name of the config being timed (prepended to results string)
+     * @param timerFlags bitfield of TimerFlags values indicating which timers should be reported.
+     * @param itersPerTiming the number of test/bench iterations that correspond to each
+     *        appendTimes() call, 1 when appendTimes is called for each iteration.
+     */
+    SkString getResult(const char* doubleFormat,
+                       Result result,
+                       const char* configName,
+                       uint32_t timerFlags,
+                       int itersPerTiming = 1);
+    Json::Value getJSON(uint32_t timerFlags,
+                        Result result,
+                        int itersPerTiming = 1);
+
+private:
+    int fMaxNumTimings;
+    int fCurrTiming;
+
+    SkAutoTArray<double> fWallTimes;
+    SkAutoTArray<double> fTruncatedWallTimes;
+    SkAutoTArray<double> fCpuTimes;
+    SkAutoTArray<double> fTruncatedCpuTimes;
+    SkAutoTArray<double> fGpuTimes;
+};
+
+#endif // TimerData_DEFINED