Re: [External] Re: [PATCH v4 1/1] commit-graph.c: no lazy fetch in lookup_commit_in_graph()

[Han Xin <hanxin.hx@bytedance.com>]

On Tue, Jul 12, 2022 at 4:17 AM Junio C Hamano <gitster@pobox.com> wrote:
>
> Jeff King <peff@peff.net> writes:
>
> >> 512 is probably OK in CI in an isolated environment but is too low on a
> >> typical "What you mean I'm not working? I'm waiting for the test run!"
> >> developper workstation.
> >>
> >> Conversely, which number would be too high to catch what the test is
> >> supposed to catch? Does it incur a big performance penalty to go as high
> >> as possible?
> >
> > This bit me, too. It works if I run it standalone:
> >
> >   $ ./t5330-no-lazy-fetch-with-commit-graph.sh
> >   ok 1 - setup: prepare a repository with a commit
> >   ok 2 - setup: prepare a repository with commit-graph contains the commit
> >   ok 3 - setup: change the alternates to what without the commit
> >   ok 4 - fetch any commit from promisor with the usage of the commit graph
> >   # passed all 4 test(s)
> >
> > but it fails when I run the whole test suite with "prove -j32". Or even
> > easier, just run it under "--stress":
>
> Understandable.  I am usually on a datacentre VM without graphical
> UI so the process count there is much lower than on a typical
> developer workstation.
>
> I wonder if we can just run the test without any limit?  If in an
> unattended CI situation, hopefully they will kick the job out due to
> quota, and on a developer workstation, there may be processes killed
> left and right, but that is only when the "infinite respawning" bug
> reappears.
>

The tricky thing about using ulimit is that it's tied to the entire development
station. I have tried to run the test without any limit [1], it did finally be
canceled after 6 hours.

Remove the "ulimit", once the infinite loop reappears, this test seems like a
bomb to developers that quickly consumes all resources? While "1024"
works fine with "--stress" , there are reasons to wonder if it's enough, or
maybe we can take a value like 10240 that we wouldn't normally reach?

1. https://github.com/chiyutianyi/git/runs/6962635320

Thanks
-Han Xin