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42fd2adbaa
As seen in this profile of a Twitch replay: https://perfht.ml/2K9Ydb3 we can often end up spending time in TrackBuffersManager::CodedFrameProcessing() shaving off bytes from the front off TrackBuffersManager::mInputBuffer. This requires all the remaining bytes to be memmove'd down to the start of this array. Sometimes we have close to 1MB in that buffer, and when we're just trying to consume a few hundred bytes, that becomes high overhead. So intead of using this "slice off, shuffle down" approach change TrackBuffersManager::mInputBuffer to be a new type MediaSpan, which maintains a RefPtr to a MediaByteBuffer and a span defining the subregion of the buffer we care about. This means the RemoveElementsAt(0,N) operation becomes basically free, and we can eliminate a few other copies we were doing as well. Differential Revision: https://phabricator.services.mozilla.com/D34661 --HG-- extra : moz-landing-system : lando
112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include <gtest/gtest.h>
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#include <stdint.h>
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#include "MediaSpan.h"
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#include "mozilla/ArrayUtils.h"
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#include "nsAutoPtr.h"
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using namespace mozilla;
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already_AddRefed<MediaByteBuffer> makeBuffer(uint8_t aStart, uint8_t aEnd) {
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RefPtr<MediaByteBuffer> buffer(new MediaByteBuffer);
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for (uint8_t i = aStart; i <= aEnd; i++) {
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buffer->AppendElement(i);
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}
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return buffer.forget();
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}
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bool IsRangeAt(const MediaSpan& aSpan, uint8_t aStart, uint8_t aEnd,
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size_t aAt) {
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size_t length = size_t(aEnd) - size_t(aStart) + 1;
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if (aAt + length > aSpan.Length()) {
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return false;
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}
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for (size_t i = 0; i < length; i++) {
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if (aSpan[aAt + i] != uint8_t(aStart + i)) {
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return false;
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}
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}
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return true;
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}
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bool IsRange(const MediaSpan& aSpan, uint8_t aStart, uint8_t aEnd) {
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return IsRangeAt(aSpan, aStart, aEnd, 0);
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}
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TEST(MediaSpan, AppendToFromSpan)
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{
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RefPtr<MediaByteBuffer> buffer1 = makeBuffer(0, 9);
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MediaSpan span1 = MediaSpan(buffer1);
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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MediaSpan span2 = span1.From(5);
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EXPECT_EQ(span2.Length(), size_t(5));
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EXPECT_TRUE(IsRange(span2, 5, 9));
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RefPtr<MediaByteBuffer> buffer2 = makeBuffer(10, 19);
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EXPECT_EQ(buffer2->Length(), size_t(10));
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span2.Append(buffer2);
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// Span2 should be: [5...19]
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EXPECT_EQ(span2.Length(), size_t(15));
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EXPECT_TRUE(IsRange(span2, 5, 19));
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// Span1 should not be modified by the append to span2.
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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}
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TEST(MediaSpan, AppendToToSpan)
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{
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RefPtr<MediaByteBuffer> buffer1 = makeBuffer(0, 9);
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MediaSpan span1 = MediaSpan(buffer1);
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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MediaSpan span2 = span1.To(5);
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// Span2 should be [0...4]
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EXPECT_EQ(span2.Length(), size_t(5));
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EXPECT_TRUE(IsRange(span2, 0, 4));
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RefPtr<MediaByteBuffer> buffer2 = makeBuffer(10, 19);
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EXPECT_EQ(buffer2->Length(), size_t(10));
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span2.Append(buffer2);
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// Span2 should be: [0...4][10...19]
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EXPECT_EQ(span2.Length(), size_t(15));
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EXPECT_TRUE(IsRangeAt(span2, 0, 4, 0));
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EXPECT_TRUE(IsRangeAt(span2, 10, 19, 5));
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// Span1 should not be modified by the append to span2.
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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}
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TEST(MediaSpan, RemoveFront)
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{
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RefPtr<MediaByteBuffer> buffer1 = makeBuffer(0, 9);
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MediaSpan span1 = MediaSpan(buffer1);
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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MediaSpan span2(span1);
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EXPECT_EQ(span2.Length(), size_t(10));
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span2.RemoveFront(5);
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// Span2 should now be [5...9]
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EXPECT_EQ(span2.Length(), size_t(5));
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EXPECT_TRUE(IsRange(span2, 5, 9));
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// Span1 should be unaffected.
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EXPECT_EQ(span1.Length(), size_t(10));
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EXPECT_TRUE(IsRange(span1, 0, 9));
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}
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