Is "-fno-inline -fno-optimize-sibling-calls” still on the table? Thanks, Geoff
> On Jun 24, 2020, at 10:28 AM, Mark Lam <mark....@apple.com> wrote: > > I forgot to add ... > >> On Jun 24, 2020, at 10:26 AM, Mark Lam <mark....@apple.com >> <mailto:mark....@apple.com>> wrote: >> >> Based on all the feedback given so far, it looks like we can move forward >> with the following plan: >> 1. JSC Debug test bots will build their own local jsc with O3 before running >> the tests. > > 1.5 JSC EWS bot will also run with an O3 Debug build. > > Mark > >> 2. The rest of the build and test bots will remain unchanged. >> >> Let's move forward with this and get the Debug JSC test bot functional again. >> >> Thanks. >> >> Mark >> >> >>> On Jun 19, 2020, at 2:58 PM, Alexey Proskuryakov <a...@webkit.org >>> <mailto:a...@webkit.org>> wrote: >>> >>> >>> >>>> 19 июня 2020 г., в 1:11 PM, Mark Lam <mark....@apple.com >>>> <mailto:mark....@apple.com>> написал(а): >>>> >>>> >>>> >>>>> On Jun 19, 2020, at 10:24 AM, Geoffrey Garen <gga...@apple.com >>>>> <mailto:gga...@apple.com>> wrote: >>>>> >>>>>>> On Jun 19, 2020, at 8:04 AM, Geoffrey Garen <gga...@apple.com >>>>>>> <mailto:gga...@apple.com>> wrote: >>>>>>> >>>>>>> Can you explain more about what "O3 with no-inlining” is? How does >>>>>>> --force-opt=O3 avoid inlining? Would this fully resolve Simon concern >>>>>>> about stack traces, or would something still be different about stack >>>>>>> traces? >>>>>> There doesn't exist a way to do this now, but it'd be trivial to add a >>>>>> way. I won't claim it fixes all stack traces differences, but I'd think >>>>>> compiling using "-fno-inline -fno-optimize-sibling-calls" would get us >>>>>> pretty far in crashing stack traces being similar enough. >>>>> >>>>> Sounds good. >>>>> >>>>> I think we should try to refine the proposal along these lines, to >>>>> minimize the downsides. I won’t speak for Simon, but for me, being able >>>>> to ensure a clear backtrace from a bot would be a big improvement. >>>>> >>>>>>> And again, I think this discussion would get a lot more focused if the >>>>>>> change could apply only to JSC code, and not also to WTF code. >>>>>> I believe Mark's proposal, initially, is just to make JSC do this. So I >>>>>> don't see the point of compiling WTF differently. JSC can kick off its >>>>>> own build, and run Debug+O3 tests faster than it can run Debug+O0 tests. >>>>>> Given people working on JSC want this, and people working on JSC defend >>>>>> these tests, and that these test results are more stable (see below), we >>>>>> should make this change for JSC. >>>>>> >>>>>> I was trying to convince folks defending non-JSC testing, that they too, >>>>>> should want this. I'm not going to pull teeth here. If folks want their >>>>>> tests to take ~10x longer to run, they're entitled to make that tradeoff. >>>>> >>>>> Got it. >>>> >>>> I'm of the same mind as Saam. We want this change for the JSC bots, and >>>> from the time measurements I’ve collected, we can afford to do a clean >>>> build for the JSC Debug test runs using O3, and still come out way ahead. >>> >>> This seems like a reasonable plan. You didn't mention what hardware you >>> measured with, but it seems certain to be beneficial on any current >>> hardware. >>> >>> I need to mention that we saw unexplained and very large impact on JSC test >>> speed from enabling/disabling TCSM. That may be a good thing to look into >>> while optimizing JSC test speed. >>> >>> - Alexey >>> >>> >>>> As for non-JSC test runs, I have not actually measured what the time >>>> savings are. Given there is resistance to going with O3 there, we don’t >>>> have to share the build artifacts for running the tests. JSC test runs >>>> should be able to just build JSC for each O3 Debug JSC test run and it is >>>> still a win over the current status quo i.e. test runs never complete. >>>> >>>> Regarding Geoff’s earlier question about whether I know for sure that >>>> switching to O3 will fix the current Debug JSC bot failures to run tests, >>>> the answer is I’m not certain. The failure is a timeout due to the master >>>> bot not seeing any output from the tester bot for more than 20 minutes. >>>> I’ve not been able to reproduce this yet. But with a Debug build test run >>>> taking 4+ hours, it can only be a progression to switch the Debug JSC test >>>> bots to O3. >>>> >>>> Mark >>>> >>>> >>>>> >>>>>>> And again, on the run more tests front, it would be helpful to know >>>>>>> whether this change was enough to get the stress tests running or not. >>>>>> My experience running the tests locally supports this fully. I don't get >>>>>> timeouts when running O3+Debug locally. When running Debug+O0 locally, >>>>>> I'd get timeouts all the time, and the total test run would take ~4-8 >>>>>> hours. We can wait for official confirmation from Mark. >>>>> >>>>> Alexey, do the JSC stress tests run now on bots? If not, how fast would >>>>> they need to run in order to be eligible to run on bots? >>>>> >>>>> Thanks, >>>>> Geoff >>>>> >>>>>> >>>>>> - Saam >>>>>> >>>>>>> >>>>>>> Thanks, >>>>>>> Geoff >>>>>>> >>>>>>>> On Jun 18, 2020, at 9:30 PM, Saam Barati <sbar...@apple.com >>>>>>>> <mailto:sbar...@apple.com>> wrote: >>>>>>>> >>>>>>>> Why are we insisting on doing something on the bots that takes ~10x >>>>>>>> longer to run than necessary? I’d rather have that time spent running >>>>>>>> more tests. >>>>>>>> >>>>>>>> Overall, how we’re doing things now feels like a bad allocation of bot >>>>>>>> resources. The differences I see between O3 with no-inlining vs O0 is: >>>>>>>> - Some race conditions will behave differently. Race conditions are >>>>>>>> already non predictable. I don’t think we’re losing anything here. >>>>>>>> - O0 vs O3 is a different compiler. We may encounter bugs in O3 we >>>>>>>> don’t in O0, and vice versa. In general, we probably care more about >>>>>>>> O3 compiler bugs than O0, since we don’t ship O0, but ship a lot of O3. >>>>>>>> >>>>>>>> (And if we’re going to insist on “I want it to run what I build at my >>>>>>>> desk”: I run debug with O3 at my desk, and I can run debug tests in a >>>>>>>> reasonable amount of time now.) >>>>>>>> >>>>>>>> In evaluating what’s the better setup, I think it’s helpful to think >>>>>>>> about this from the other side. Let’s imagine we had Debug+O3 as our >>>>>>>> current setup. And someone proposed to move it to O0 and make our >>>>>>>> tests take ~10x longer. I think that’d be a non-starter. >>>>>>>> >>>>>>>> - Saam >>>>>>>> >>>>>>>>> On Jun 17, 2020, at 9:48 PM, Simon Fraser <simon.fra...@apple.com >>>>>>>>> <mailto:simon.fra...@apple.com>> wrote: >>>>>>>>> >>>>>>>>> I also object to losing good stack traces for crashes on Debug bots. >>>>>>>>> >>>>>>>>> Also, I don't think Debug bots should build something different from >>>>>>>>> what I build at my desk. >>>>>>>>> >>>>>>>>> Simon >>>>>>>>> >>>>>>>>>> On Jun 17, 2020, at 1:36 PM, Mark Lam <mark....@apple.com >>>>>>>>>> <mailto:mark....@apple.com>> wrote: >>>>>>>>>> >>>>>>>>>> Hi folks, >>>>>>>>>> >>>>>>>>>> We're planning to switch the JSC EWS bot and build.webkit.org >>>>>>>>>> <http://build.webkit.org/> Debug build and test bots to building >>>>>>>>>> with the following set first: >>>>>>>>>> ./Tools/Scripts/set-webkit-configuration --force-opt=O3 >>>>>>>>>> >>>>>>>>>> This means the Debug builds will be built with optimization level >>>>>>>>>> forced to O3. >>>>>>>>>> >>>>>>>>>> Why are we doing this? >>>>>>>>>> 1. So that the JSC EWS will start catching ASSERT failures. >>>>>>>>>> 2. JSC stress test Debug bots have been timing out and not running >>>>>>>>>> tests at all. Hopefully, this change will fix this issue. >>>>>>>>>> 3. Tests will run to completion faster and we’ll catch regressions >>>>>>>>>> sooner. >>>>>>>>>> >>>>>>>>>> The downside: crash stack traces will be like Release build stack >>>>>>>>>> traces. But I don’t think we should let this deter us. It’s not >>>>>>>>>> like there’s no stack information. And just as we do with debugging >>>>>>>>>> Release build test failures, we can always do a Debug build locally >>>>>>>>>> to do our debugging. >>>>>>>>>> >>>>>>>>>> We would like to apply this change to all Debug build and test bots, >>>>>>>>>> not just the JSC ones. Does anyone strongly object to this change? >>>>>>>>>> >>>>>>>>>> Thanks. >>>>>>>>>> >>>>>>>>>> Cheers, >>>>>>>>>> Mark >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> webkit-dev mailing list >>>>>>>>>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>>>>>>>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>>>>>>>>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> webkit-dev mailing list >>>>>>>>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>>>>>>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>>>>>>>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >>>>>>>> _______________________________________________ >>>>>>>> webkit-dev mailing list >>>>>>>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>>>>>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>>>>>>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >>>>>>> >>>>>> >>>>> >>>>> _______________________________________________ >>>>> webkit-dev mailing list >>>>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>>>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >>>> >>>> _______________________________________________ >>>> webkit-dev mailing list >>>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >>> >>> - Alexey >> >> _______________________________________________ >> webkit-dev mailing list >> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >> https://lists.webkit.org/mailman/listinfo/webkit-dev > > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> > https://lists.webkit.org/mailman/listinfo/webkit-dev > <https://lists.webkit.org/mailman/listinfo/webkit-dev>
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