Right, exactly. I am arguing that testing PGO, which is a buggy optimization pass, incurs too much developer cost to justify a "5-20%" talos improvement on select benchmarks. On Linux, which is a very small percentage of our market share, and where distributions make their own builds anyway.
Whether we'd tell distributions that PGO was unsupported: it actually seems difficult to say that it *is* supported, even now. PGO bugs will likely be highly dependent on the environment and compiler version, which are won't be exactly the same anywhere as they are on Windows. -David On Thursday, October 11, 2012 12:32:10 AM UTC-7, Boris Zbarsky wrote: > On 10/11/12 3:05 AM, Tim Taubert wrote: > > > Also, I'm not sure how this affects Telemetry results. In terms of perf > > > measurements we'd probably need to completely ignore everything from > > > non-release builds as the results might differ heavily for some use > > > cases. > > > > I'm not following. > > > > The suggestion, as far as I can tell, is to drop Linux PGO completely. > > We woudln't have it in nightly, Aurora, Beta, or releases. Compiling > > with PGO on Linux would be an unsupported configuration that we'd > > probably advise distros against, because it wouldn't be particularly > > well-tested. > > > > So the real question is whether PGO on Linux is worth it in general to > > us, again as far as I can tell. > > > > -Boris _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
