On Tue, Apr 7, 2015, at 11:05 AM, Bill McCloskey wrote: > On Tue, Apr 7, 2015 at 5:48 AM, Benjamin Smedberg <benja...@smedbergs.us> > wrote: > > > With desktop e10s on there can be a noticeable delay after switching tabs > > where there is a throbber displayed before the page content. > > > > When the user switches tabs, we allow the content process 300ms to send > layer information to the parent. During that time, we show the previous > tab. If no layers are received after 300ms, we show the spinner. > > > > Is the duration of this delay measured in telemetry anywhere, and do we > > have criteria for how much delay is acceptable in this case? If e10s were > > off, do we expect that this same delay would occur but would just show up > > as a jank switching tabs? Or is this a perf problem unique to e10s? > > > > We don't have telemetry yet. I've done some measurements and haven't > found > any cases where tab switching consistently takes longer in e10s. However, > it's certainly possible that it does on average. Either way, it's hard to > investigate until we can reproduce the problem. > > The switch is definitely more noticeable in e10s because non-e10s would > just jank. A spinner (especially a low-quality animated gif like the one > we > have) is easier to notice than jank. We've considered a couple options
So, assuming there's content script eating up cycles, right now the e10s case will essentially always be worse than the non-e10s case, right? In the non-e10s case the chrome JS for switching tabs will get hung up and result in jank, but then when it gets to run the repaint should be very fast because the layer tree is in-process. In the e10s case the chrome JS will run, then we wait on IPC for the layer tree which will be held up by the content JS, then we have to transmit the layer tree via IPC, and only then can we paint. Short of doing the layer IPC on a different IPC channel this doesn't seem fixable. Alternately we could focus on running >1 content process as others have noted, since that limits the content script problem to tabs running in the same process as the tab you're switching to. -Ted _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
