When MiniBrowser for wincairo accesses a sites, it sometimes consumes CPU greedily. How to reproduce. 1) Access http://news.yahoo.co.jp/ with MiniBrowser for wincairo. 2) Reload the page. 3) Check task-manager, you will see NetworkProcess consumes much CPU resource.
The cause of this issue is that CurlRequestSchduler::workerThread doesn't stop/sleep at ::select. When WebKit gets response headers the CurlRequest makes the curl_easy_handle PAUSED. We do not have to check paused handles by ::select but they are watched. And if a handle is ready for read/write ::select goes through without any wait. This makes worker thread busy loop. The root cause is NetworkDataTaskCurl::invokeDidReceiveResponse() doesn't handle PolicyAction::Ignore properly, and active jobs in CurlRequestSceduler aren't removed until timeout. So we have to call invalidateAndCancel() when policy action is Ignore.
Created attachment 404427 [details] Patch
Committed r264485: <https://trac.webkit.org/changeset/264485> All reviewed patches have been landed. Closing bug and clearing flags on attachment 404427 [details].
<rdar://problem/65695976>