Firefox 92 on POWER

Date: 2021-09-13T19:31:00-07:00

Location: www.talospace.com

Firefox 92 is out. Alongside some solid DOM and CSS improvements, the most interesting bug fix I noticed was a patch for open alerts slowing down other tabs in the same process. In the absence of a JIT we rely heavily on Firefox's multiprocessor capabilities to make the most of our multicore beasts, and this apparently benefits (among others, but in particular) the Google sites we unfortunately have to use in these less-free times. I should note for the record that on this dual-8 Talos II (64 hardware threads) I have

dom.ipc.processCount

modestly increased to 12 from the default of 8 to take a little more advantage of the system when idle, which also takes down fewer tabs in the rare cases when a content process bombs out. The delay in posting this was waiting for the

firefox-appmenu patches

, but I decided to just build it now and add those in later. The

.mozconfigs and LTO-PGO patches

are unchanged from Firefox 90/91.

Meanwhile, in OpenPOWER JIT progress, I'm about halfway through getting the Wasm tests to pass, though I'm currently hung up on a memory corruption bug while testing Wasm garbage collection. It's our bug; it doesn't happen with the C++ interpreter, but unfortunately like most GC bugs it requires hitting it "just right" to find the faulty code. When it all passes, we'll pull everything up to 91ESR for the MVP, and you can try building it. If you want this to happen faster, please pitch in and help.