On Sat, Jul 09, 2022 at 02:23:36PM +0200, Michael J Gruber wrote:

quoted

+run_with_limited_processses () {
+       # bash and ksh use "ulimit -u", dash uses "ulimit -p"
+       if test -n "$BASH_VERSION"
+       then
+               ulimit_max_process="-u"
+       elif test -n "$KSH_VERSION"
+       then
+               ulimit_max_process="-u"
+       fi
+       (ulimit ${ulimit_max_process-"-p"} 512 && "$@")
+}

This new test fails for me unless I increase max_processes. 1024 works.

I haven't bisected the number of prcesses ... This is higly system
dependent. I even run a slim environment (i3wm) but having chrome or
such running probably makes quite a difference.

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":

  $ ./t5330-no-lazy-fetch-with-commit-graph.sh  --stress
  [...]
  + run_with_limited_processses env GIT_TRACE=/home/peff/compile/git/t/trash directory.t5330-no-lazy-fetch-with-commit-graph.stress-30/trace.txt git -C with-commit-graph fetch origin ba19607defe740988a69e98bced331083e02bdd6
error: last command exited with $?=128
not ok 4 - fetch any commit from promisor with the usage of the commit graph

  $ cat trash*.stress-failed/err
  [...]
  error: cannot fork() for index-pack: Resource temporarily unavailable
  fatal: fetch-pack: unable to fork off index-pack

-Peff