[llvm-dev] False positive notifications around commit notifications

[Chris Lattner via llvm-dev]

> On Oct 11, 2021, at 12:06 PM, Michael Kruse via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Am Mo., 11. Okt. 2021 um 12:57 Uhr schrieb David Blaikie via llvm-dev
> <llvm-dev at lists.llvm.org>:
>> Here's a fun one: https://lab.llvm.org/buildbot/#/builders/164/builds/3428 - a buildbot failure with a single blame (me) - but I hadn't committed in the last few days, so I was confused. Turns out its from a change committed 3 months ago - and the failure is a timeout.
>> 
>> Given the number of buildbot timeout false positives, I honestly wouldn't be averse to saying timeouts shouldn't produce fail-mail & are the responsibility of buildbot owners to triage. I realize we can actually submit code that leads to timeouts, but on balance that seems rare compared to the number of times its a buildbot configuration issue instead. (though open to debate on that for sure)
> 
> Wow, that bot does not collapse buildrequests and is indeed 3 months
> behind due to not being fast enough to keep up with LLVM's commit
> rate. Even if the bot was reliable, getting notified 3 months later
> isn't useful.
> From the wildly varying duration the test step takes (5 - 33 minutes;
> not the build step, it is doing incremental builds), I assume that the
> worker is running other things in parallel, maybe another worker, such
> that the buildjob sometimes is starving and causing the timeout. IMHO
> buildbots should not run other heavy jobs in parallel.


I agree with David re: timeouts should only go to the owner of the bot.

Separately, is the arc-builder builder actually useful?  Should we remove it?

-Chris