Re: [PATCH v3 24/34] t/perf/p7519: speed up test using "test-tool touch"
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jul 13, 2021, 17:47 UTC
- Message-ID
- <xmqq1r822jj8.fsf@gitster.g>
- In-Reply-To
- <CABPp-BF+GiAZVxeC+MAr6pSssRpSi2pNwHLrxUp9HvrOhUBieg@mail.gmail.com>
Elijah Newren <newren@gmail.com> writes:
Show 19 quoted lines
> On Tue, Jul 13, 2021 at 10:10 AM Jeff Hostetler <git@jeffhostetler.com> wrote: >> >> a quick test on my Windows machine shows that >> >> test_seq 1 10000 | xargs touch >> >> takes 3.1 seconds. >> >> just a simple >> >> test_seq 1 10000 >/dev/null >> >> take 0.2 seconds. >> >> using my test-tool helper cuts that time in half. > > Yeah, test_seq is pretty bad; it's just a loop in shell. Is there a > 'seq' on windows, and does using it instead of test_seq make things > faster with Ævar's suggested command?
Unless I am misreading Jeff's message, I do not think that makes sense. Counting to 10000 in shell loop is trivial (0.2 seconds), but letting touch invoked 10000 times to create (or smudge mtime of, but I suspect that is not what is going on here) 10000 files takes 3.1 seconds, and of course a native binary that creates 10000 files with a single invocation would be faster.
> I'd really like to modify test_seq to use seq when it's available and > fall back to the looping-in-shell when we need to for various > platforms.
So, if I am reading Jeff correctly, that optimizes something that is not a bottleneck.
> Maybe it'd even make sense to write a 'test-tool seq' and make > test_seq use that just so we can rip out that super lame shell > looping.