Bug 136199 – Remove scheduling code from network process

• Component: Page Loading
• Status: RESOLVED FIXED

[Antti Koivisto]

It is not really used.

[Antti Koivisto]

Created attachment 237045 [details]
patch

[Antti Koivisto]

Created attachment 237047 [details]
patch

[Darin Adler]

Comment on attachment 237047 [details]
patch

OK. Good to delete this if it’s not being used. But here’s hoping we do these kinds of optimizations as appropriate in the networking layers.

[Antti Koivisto]

Hmm, maybe we can't do this yet. NSURLRequest priorities have some bugs that cause problems in releases prior to Yosemite and so haven't been enabled. If we don't do prioritization ourselves then performance may suffer. :(

[Alexey Proskuryakov]

So we don't do any of the prioritization in WebProcess? If so, how do we reprioritize in NetworkProcess?

[Antti Koivisto]

In network process mode the web process side ResourceLoadScheduler is just a dumb proxy (WebKit::WebResourceLoadScheduler overrides the WebCore implementation). The actual priority-based scheduling is done by this copy code that I was trying to get rid of (NetworkResourceLoadScheduler) when the networking layer priorities are not supported.

[Antti Koivisto]

Turns out that the network process scheduling code is never really used. Scheduling requires priority but making the requests we do  

void WebResourceLoadScheduler::scheduleLoad(ResourceLoader* resourceLoader, CachedResource* resource, ResourceLoadPriority priority, bool shouldClearReferrerOnHTTPSToHTTPRedirect)
{
    ASSERT(resourceLoader);
    ASSERT(priority != ResourceLoadPriorityUnresolved);
    priority = ResourceLoadPriorityHighest;

(the priorities that we tell to CFNetwork are part of ResourceRequest and are not affected by this)

This mean the network process scheduling has never really been used and we can remove it without risking regressions.

[Antti Koivisto]

https://trac.webkit.org/r172927