Bug 672207. imglib-telemetry: record the full time it takes to decode images. r=jlebar,joe

Do this by accumulating decode latency in mDecodeTime which is added to imgDecodeWorker.

modules/libpr0n/src/RasterImage.cpp

@@ -2711,6 +2711,9 @@ imgDecodeWorker::Run()
   TimeDuration decodeLatency = TimeStamp::Now() - start;
   Telemetry::Accumulate(Telemetry::IMAGE_DECODE_LATENCY, PRInt32(decodeLatency.ToMicroseconds()));
 
+  // accumulate the total decode time
+  mDecodeTime += decodeLatency;
+
   // Flush invalidations _after_ we've written everything we're going to.
   // Furthermore, if this is a redecode, we don't want to do progressive
   // display at all. In that case, let Decoder::PostFrameStop() do the
@@ -2723,6 +2726,7 @@ imgDecodeWorker::Run()
 
   // If the decode finished, shutdown the decoder
   if (image->mDecoder && image->IsDecodeFinished()) {
+    Telemetry::Accumulate(Telemetry::IMAGE_DECODE_TIME, PRInt32(mDecodeTime.ToMicroseconds()));
     rv = image->ShutdownDecoder(RasterImage::eShutdownIntent_Done);
     if (NS_FAILED(rv)) {
       image->DoError();

modules/libpr0n/src/RasterImage.h

@@ -64,6 +64,7 @@
 #include "imgFrame.h"
 #include "nsThreadUtils.h"
 #include "DiscardTracker.h"
+#include "mozilla/TimeStamp.h"
 #ifdef DEBUG
   #include "imgIContainerDebug.h"
 #endif
@@ -571,6 +572,7 @@ class imgDecodeWorker : public nsRunnable
 
   private:
     nsWeakPtr mContainer;
+    TimeDuration mDecodeTime; // the default constructor initializes to 0
 };
 
 // Asynchronous Decode Requestor

toolkit/components/telemetry/TelemetryHistograms.h

@@ -83,7 +83,8 @@ HISTOGRAM(MAC_INITFONTLIST_TOTAL, 1, 30000, 10, EXPONENTIAL, "gfxMacPlatformFont
 #endif
 HISTOGRAM(SHUTDOWN_OK, 0, 1, 2, BOOLEAN, "Did the browser start after a successful shutdown")
 
-HISTOGRAM(IMAGE_DECODE_LATENCY, 50, 5000000, 100, EXPONENTIAL, "Time spent decoding an image chunk (us)")
+HISTOGRAM(IMAGE_DECODE_LATENCY, 50,  5000000, 100, EXPONENTIAL, "Time spent decoding an image chunk (us)")
+HISTOGRAM(IMAGE_DECODE_TIME,    50, 50000000, 100, EXPONENTIAL, "Time spent decoding an image (us)")
 
 /**
  * Networking telemetry