290211 2025-03-21 13:39:00 -0700 Stop using IOChannel in NetworkCache 2025-03-23 21:49:43 -0700 1 1 1 Unclassified WebKit WebKit Misc. WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 nham nham webkit-bug-importer oldest_to_newest 2105119 0 nham 2025-03-21 13:39:00 -0700 We've seen sporadic logs of page loads taking minutes to complete when the system is under load. The logs are showing that the disk cache lookup in NetworkProcess is getting preempted for minutes and it's being serviced on a default overcommit dispatch queue at priority 4. We think this might be because we're using dispatch_io to read the records, which internally basically parks a thread on the overcommit queue in pread and somehow the priority propagation isn't always working and sometimes leading to the pread being stuck and preempted at pri 4. Since dispatch_io is basically buying us nothing here other than using more threads and making it harder to follow what's going on, we should probably just stop using it and instead make I/O syscalls directly on the network cache's I/O queue. 2105120 1 nham 2025-03-21 13:39:01 -0700 <rdar://problem/142645876> 2105124 2 nham 2025-03-21 13:46:53 -0700 Pull request: https://github.com/WebKit/WebKit/pull/42840 2105492 3 ews-feeder 2025-03-23 21:49:41 -0700 Committed 292576@main (0b589ff5c2f2): <https://commits.webkit.org/292576@main> Reviewed commits have been landed. Closing PR #42840 and removing active labels.