Bug 262380

Summary:	RemoteDisplayListRecorder should lazily allocate a SharedVideoFrameReader
Product:	WebKit	Reporter:	Simon Fraser (smfr) <simon.fraser>
Component:	WebKit Process Model	Assignee:	Simon Fraser (smfr) <simon.fraser>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	simon.fraser, webkit-bug-importer, youennf
Priority:	P2	Keywords:	InRadar
Version:	WebKit Local Build
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=258379

Description Simon Fraser (smfr) 2023-09-29 10:16:05 PDT

Every RemoteDisplayListRecorder currently has a SharedVideoFrameReader by value. 99% of them will never use it. so it should be allocated lazily.

Comment 1 Simon Fraser (smfr) 2023-09-29 10:16:47 PDT

There is some cost here to:

_kernelrpc_mach_port_mod_refs_trap
WTF::MachSendRight::MachSendRight(WTF::MachSendRight const&)
WebKit::SharedVideoFrameReader::SharedVideoFrameReader(WTF::RefPtr<WebKit::RemoteVideoFrameObjectHeap, WTF::RawPtrTraits<WebKit::RemoteVideoFrameObjectHeap>, WTF::DefaultRefDerefTraits<WebKit::RemoteVideoFrameObjectHeap>>&&, WebCore::ProcessIdentity const&, WebKit::SharedVideoFrameReader::UseIOSurfaceBufferPool)
WebKit::RemoteDisplayListRecorder::create(WebCore::ImageBuffer&, WTF::ObjectIdentifierGeneric<WebCore::RenderingResourceIdentifierType, WTF::ObjectIdentifierThreadSafeAccessTraits>, WebKit::RemoteRenderingBackend&)
WebKit::RemoteRenderingBackend::didCreateImageBuffer(WTF::Ref<WebCore::ImageBuffer, WTF::RawPtrTraits<WebCore::ImageBuffer>>)

Comment 2 Simon Fraser (smfr) 2023-09-29 10:22:04 PDT

I did the same on the other side of the connection in bug 258379.

Comment 3 Radar WebKit Bug Importer 2023-10-06 10:17:16 PDT

<rdar://problem/116586176>

Comment 4 Simon Fraser (smfr) 2023-11-07 18:00:42 PST

Pull request: https://github.com/WebKit/WebKit/pull/20141

Comment 5 EWS 2023-11-08 13:39:07 PST

Committed 270404@main (34b59cbee757): <https://commits.webkit.org/270404@main>

Reviewed commits have been landed. Closing PR #20141 and removing active labels.