On Sat, Mar 31, 2018 at 10:12 AM Steve Fink <sf...@mozilla.com> wrote:
> Yes, sorry, a couple of people pointed that out to me privately. And I > did get that mixed up; I was assuming processors, despite the page > specifically pointing out "physical cores". > > I still think there's something to be kept in mind here, though. Even > with 4 processors (2 hyperthreaded cores or whatever), it's never > correct to assume that running something on a different thread is a gold > bullet for performance problems. I'm all for increasing the concurrency > of our code as long as we ensure that it doesn't hurt in the case of low > levels of actual parallelism. > > What that means in practice, I'm not entirely sure, but it does seem > like we should be more conscious about thread priorities and global > thread pool management. Also, lock contention is a real thing. It has > been coming up here and there and wiping out parallelization gains. > We have bug 1366358 filed about properly specifying thread priorities, which is especially important for systems with lower number of cores. Last year during the Quantum Flow project we came across various bugs which manifested as various threads running at a higher priority than some very important thread (such as the compositor thread) resulting in situations where we couldn't run any code on the compositor thread for several frames which show up as whole-UI jank. I think fixing the dependencies of that bug is a good systematic protection against bad performance situations like that. > > On 3/28/18 10:27 AM, Ben Kelly wrote: > > That page says "physical cores", so its not taking into account hyper > > threading, right? So even a high end macbook pro falls in that category? > > > > On Tue, Mar 27, 2018 at 5:02 PM, Mike Conley <mcon...@mozilla.com > > <mailto:mcon...@mozilla.com>> wrote: > > > > Thanks for drawing attention to this, sfink. > > > > This is likely to become more important as we continue to scale up > our > > parallelization with content processes and threads. > > > > On 21 March 2018 at 14:54, Steve Fink <sf...@mozilla.com > > <mailto:sf...@mozilla.com>> wrote: > > > > > Just to drive home a point, let's play a game. > > > > > > First, guesstimate what percentage of our users have systems > > with 2 or > > > fewer cores. > > > > > > Then visit > > https://hardware.metrics.mozilla.com/#goto-cpu-and-memory > > <https://hardware.metrics.mozilla.com/#goto-cpu-and-memory> to > > > check your guess. > > > > > > (I didn't say it was a *fun* game.) > > > > > > > > > _______________________________________________ > > > dev-platform mailing list > > > dev-platform@lists.mozilla.org > > <mailto:dev-platform@lists.mozilla.org> > > > https://lists.mozilla.org/listinfo/dev-platform > > <https://lists.mozilla.org/listinfo/dev-platform> > > > > > _______________________________________________ > > dev-platform mailing list > > dev-platform@lists.mozilla.org <mailto: > dev-platform@lists.mozilla.org> > > https://lists.mozilla.org/listinfo/dev-platform > > <https://lists.mozilla.org/listinfo/dev-platform> > > > > > > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform > _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
