I am talking about requiring SSE2. That is a larger (but still quite small) population, but the upside of being able to turn on SSE2 optimizations by default is an important benefit. I've discussed and confirmed this with Firefox product management.
So yes, the plan of record is to require SSE2 starting in Firefox 49, and I will update the tracking bugs to reflect that. --BDS On Fri, May 6, 2016 at 1:17 PM, Gregory Szorc <g...@mozilla.com> wrote: > On Fri, May 6, 2016 at 9:39 AM, Benjamin Smedberg <benja...@smedbergs.us> > wrote: > >> I agree that we should drop support for non-SSE2. It mattered 7 years ago >> (see https://bugzilla.mozilla.org/show_bug.cgi?id=500277) but it really >> doesn't matter now. >> > > Wait - are we talking about requiring SSE or SSE2? The thread up to this > point was talking about requiring just SSE, not SSE2. I just want to make > sure we're on the same page since according to mhoye's post the non-SSE2 > population is ~25x larger than the non-SSE population... > > >> >> We do need to avoid updating these users to a build that will crash, and >> do the same "unsupported" messaging we're doing for old versions of MacOS. >> Gregory, will you own that? You will probably need to add CPU feature >> detection to the update URL/params for 47, or use some kind of system addon >> to shunt these users off the main update path. >> > > Given that 47 is in Beta, is it too late/risky to make this change on that > channel? Should we revert to VS2013 on Aurora/48 and make the updater > modifications on that channel? I think this will have minimal negative > impact, as most of the impact to changing toolchains would be on central, > as that is where most developers and automation live. > > >> >> On Fri, May 6, 2016 at 10:10 AM, Mike Hoye <mh...@mozilla.com> wrote: >> >>> On 2016-05-06 12:26 AM, Gregory Szorc wrote: >>> >>>> FWIW, the crashes we've seen so far are from incorrectly emitted movss >>>> instructions. This instruction is part of the original SSE instruction >>>> set, >>>> which was initially unveiled by Intel on the Pentium 3 in 1999 and >>>> later by >>>> AMD on the Duron and Athlon XP in 2000-2001. I'm not sure why we still >>>> need >>>> Firefox to run on processors manufactured in the 90s. >>>> >>> Per an IRC conversation with chutten, Firefox users on CPUs that do not >>> support SSE are 0.015% of our user base. (compared to 0.4% for no-SSE2). A >>> third of those are on otherwise-unsupported configurations (pre-SP3 XP, >>> etc), this work provides continuity of support to 0.01% of our users. >>> >>> - mhoye >>> >>> >>> 09:59 <chutten> So, to put it clearly and precisely, of the Firefox >>> Population in release and beta who are reporting at least base telemetry >>> collection on machines running supported configurations, only 0.01% cannot >>> definitively say they have SSE. >>> 10:00 <chutten> (according to a 1% random sample as stored in the >>> longitudinal dataset) >>> >>> _______________________________________________ >>> 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
