Bug 224166

Summary:	Wasted vector capacity in ImageSource
Product:	WebKit	Reporter:	Simon Fraser (smfr) <simon.fraser>
Component:	Images	Assignee:	Said Abou-Hallawa <sabouhallawa>
Status:	NEW ---
Severity:	Normal	CC:	sabouhallawa, simon.fraser, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Unspecified
OS:	Unspecified

Description Simon Fraser (smfr) 2021-04-03 17:26:54 PDT

ImageSource wastes vector capacity in m_frameCommitQueue. On YouTube.com:

Wasted capacity: 11264 bytes (used 0 of 11264 bytes, utilization: 0.00%) - 44 allocations
5   0x11a7f06cd WTF::VectorBuffer<WebCore::ImageSource::ImageFrameRequest, 8ul, WTF::FastMalloc>::VectorBuffer()
6   0x11a7f03f5 WTF::VectorBuffer<WebCore::ImageSource::ImageFrameRequest, 8ul, WTF::FastMalloc>::VectorBuffer()
7   0x11a7f03b5 WTF::Deque<WebCore::ImageSource::ImageFrameRequest, 8ul>::Deque()
8   0x11a7e5155 WTF::Deque<WebCore::ImageSource::ImageFrameRequest, 8ul>::Deque()
9   0x11a7e4f86 WebCore::ImageSource::ImageSource(WebCore::BitmapImage*, WebCore::AlphaOption, WebCore::GammaAndColorProfileOption)
10  0x11a7e5209 WebCore::ImageSource::ImageSource(WebCore::BitmapImage*, WebCore::AlphaOption, WebCore::GammaAndColorProfileOption)
11  0x11a6ea517 WebCore::ImageSource::create(WebCore::BitmapImage*, WebCore::AlphaOption, WebCore::GammaAndColorProfileOption)
12  0x11a6ea406 WebCore::BitmapImage::BitmapImage(WebCore::ImageObserver*)
13  0x11a6ea58d WebCore::BitmapImage::BitmapImage(WebCore::ImageObserver*)
14  0x1183375cb WebCore::BitmapImage::create(WebCore::ImageObserver*)
15  0x11a7d360a WebCore::Image::create(WebCore::ImageObserver&)
16  0x11a2d1146 WebCore::CachedImage::createImage()
17  0x11a2d4c59 WebCore::CachedImage::updateBufferInternal(WebCore::SharedBuffer&)
18  0x11a2d5184 WebCore::CachedImage::updateBuffer(WebCore::SharedBuffer&)
19  0x11a25dfef WebCore::SubresourceLoader::didReceiveDataOrBuffer(char const*, int, WTF::RefPtr<WebCore::SharedBuffer, WTF::RawPtrTraits<WebCore::SharedBuffer>, WTF::DefaultRefDerefTraits<WebCore::SharedBuffer> >&&, long long, WebCore::DataPayloadType)
20  0x11a25dd41 WebCore::SubresourceLoader::didReceiveData(char const*, unsigned int, long long, WebCore::DataPayloadType)
21  0x1071cceda WebKit::WebResourceLoader::didReceiveData(IPC::ArrayReference<unsigned char, 18446744073709551615ul> const&, long long)
22  0x1077d7629 void IPC::callMemberFunctionImpl<WebKit::WebResourceLoader, void (WebKit::WebResourceLoader::*)(IPC::ArrayReference<unsigned char, 18446744073709551615ul> const&, long long), std::__1::tuple<IPC::ArrayReference<unsigned char, 18446744073709551615ul>, long long>, 0ul, 1ul>(WebKit::WebResourceLoader*, void (WebKit::WebResourceLoader::*)(IPC::ArrayReference<unsigned char, 18446744073709551615ul> const&, long long), std::__1::tuple<IPC::ArrayReference<unsigned char, 18446744073709551615ul>, long long>&&, std::__1::integer_sequence<unsigned long, 0ul, 1ul>)

Comment 1 Simon Fraser (smfr) 2021-04-03 17:27:39 PDT

There's inline capacity in the Deque<> because of BufferSize=8.

Most images don't do async decoding so this is wasteful.

Comment 2 Radar WebKit Bug Importer 2021-04-10 17:27:12 PDT

<rdar://problem/76498514>