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Bug 1322574 - 2. Measure Android event loop latency; r=snorp

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Measure the latency of each event in the Android event loop by tagging
each event with the time that the event was posted, and then recording
the time interval between posting and processing the event. Latencies
for UI events and non-UI events are recorded separately in Telemetry.
This commit is contained in:
Jim Chen
2016-12-21 13:37:20 -05:00
parent 7eb3ca7cb3
commit 3490ca0f0c
2 changed files with 85 additions and 1 deletions
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42
widget/android/nsAppShell.cpp
View File

@@ -30,6 +30,8 @@
#include "nsToolkitCompsCID.h"
#include "nsGeoPosition.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Services.h"
#include "mozilla/Preferences.h"
#include "mozilla/Hal.h"
@@ -81,6 +83,9 @@ nsIGeolocationUpdate *gLocationCallback = nullptr;
nsAppShell* nsAppShell::sAppShell;
StaticAutoPtr<Mutex> nsAppShell::sAppShellLock;
uint32_t nsAppShell::Queue::sLatencyCount[];
uint64_t nsAppShell::Queue::sLatencyTime[];
NS_IMPL_ISUPPORTS_INHERITED(nsAppShell, nsBaseAppShell, nsIObserver)
class WakeLockListener final : public nsIDOMMozWakeLockListener {
@@ -430,6 +435,43 @@ nsAppShell::NotifyNativeEvent()
mEventQueue.Signal();
}
void
nsAppShell::RecordLatencies()
{
if (!mozilla::Telemetry::CanRecordExtended()) {
return;
}
const mozilla::Telemetry::ID timeIDs[] = {
mozilla::Telemetry::ID::FENNEC_LOOP_UI_LATENCY,
mozilla::Telemetry::ID::FENNEC_LOOP_OTHER_LATENCY
};
static_assert(ArrayLength(Queue::sLatencyCount) == Queue::LATENCY_COUNT,
"Count array length mismatch");
static_assert(ArrayLength(Queue::sLatencyTime) == Queue::LATENCY_COUNT,
"Time array length mismatch");
static_assert(ArrayLength(timeIDs) == Queue::LATENCY_COUNT,
"Time ID array length mismatch");
for (size_t i = 0; i < Queue::LATENCY_COUNT; i++) {
if (!Queue::sLatencyCount[i]) {
continue;
}
const uint64_t time = Queue::sLatencyTime[i] / 1000ull /
Queue::sLatencyCount[i];
if (time) {
mozilla::Telemetry::Accumulate(
timeIDs[i], uint32_t(std::min<uint64_t>(UINT32_MAX, time)));
}
// Reset latency counts.
Queue::sLatencyCount[i] = 0;
Queue::sLatencyTime[i] = 0;
}
}
#define PREFNAME_COALESCE_TOUCHES "dom.event.touch.coalescing.enabled"
static const char* kObservedPrefs[] = {
PREFNAME_COALESCE_TOUCHES,