From: Jeff Hostetler Date: Tue, 13 Jul 2021 19:05:18 GMT Subject: Re: [PATCH v3 24/34] t/perf/p7519: speed up test using "test-tool touch" Message-ID: In-Reply-To: <87k0lu2hw8.fsf@evledraar.gmail.com> On 7/13/21 2:18 PM, Ævar Arnfjörð Bjarmason wrote: > > On Tue, Jul 13 2021, Jeff Hostetler wrote: > >> On 7/1/21 7:09 PM, Ævar Arnfjörð Bjarmason wrote: >>> On Thu, Jul 01 2021, Jeff Hostetler via GitGitGadget wrote: >>> >>>> From: Jeff Hostetler >>>> >>>> Change p7519 to use a single "test-tool touch" command to update >>>> the mtime on a series of (thousands) files instead of invoking >>>> thousands of commands to update a single file. >>>> >>>> This is primarily for Windows where process creation is so >>>> very slow and reduces the test run time by minutes. >>>> >>>> Signed-off-by: Jeff Hostetler >>>> --- >>>> t/perf/p7519-fsmonitor.sh | 14 ++++++-------- >>>> 1 file changed, 6 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh >>>> index 5eb5044a103..f74e6014a0a 100755 >>>> --- a/t/perf/p7519-fsmonitor.sh >>>> +++ b/t/perf/p7519-fsmonitor.sh >>>> @@ -119,10 +119,11 @@ test_expect_success "one time repo setup" ' >>>> fi && >>>> mkdir 1_file 10_files 100_files 1000_files 10000_files && >>>> - for i in $(test_seq 1 10); do touch 10_files/$i; done && >>>> - for i in $(test_seq 1 100); do touch 100_files/$i; done && >>>> - for i in $(test_seq 1 1000); do touch 1000_files/$i; done && >>>> - for i in $(test_seq 1 10000); do touch 10000_files/$i; done && >>>> + test-tool touch sequence --pattern="10_files/%d" --start=1 --count=10 && >>>> + test-tool touch sequence --pattern="100_files/%d" --start=1 --count=100 && >>>> + test-tool touch sequence --pattern="1000_files/%d" --start=1 --count=1000 && >>>> + test-tool touch sequence --pattern="10000_files/%d" --start=1 --count=10000 && >>>> + >>>> git add 1_file 10_files 100_files 1000_files 10000_files && >>>> git commit -qm "Add files" && >>>> @@ -200,15 +201,12 @@ test_fsmonitor_suite() { >>>> # Update the mtimes on upto 100k files to make status think >>>> # that they are dirty. For simplicity, omit any files with >>>> # LFs (i.e. anything that ls-files thinks it needs to dquote). >>>> - # Then fully backslash-quote the paths to capture any >>>> - # whitespace so that they pass thru xargs properly. >>>> # >>>> test_perf_w_drop_caches "status (dirty) ($DESC)" ' >>>> git ls-files | \ >>>> head -100000 | \ >>>> grep -v \" | \ >>>> - sed '\''s/\(.\)/\\\1/g'\'' | \ >>>> - xargs test-tool chmtime -300 && >>>> + test-tool touch stdin && >>>> git status >>>> ' >>> Did you try to replace this with some variant of: >>> test_seq 1 10000 | xargs touch >>> Which (depending on your xargs version) would invoke "touch" >>> commands >>> with however many argv items it thinks you can handle. >>> >> >> 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. > > There's what Elijah mentioned about test_seq, so maybe it's just that. > > But what I was suggesting was using the xargs mode where it does N > arguments at a time. > > Does this work for you, and does it cause xargs to invoke "touch" with > the relevant N number of arguments, and does it help with the > performance? > > test_seq 1 10000 | xargs touch > test_seq 1 10000 | xargs -n 10 touch > test_seq 1 10000 | xargs -n 100 touch > test_seq 1 10000 | xargs -n 1000 touch The GFW SDK version of xargs does have `-n N` and it does work as advertised. And it does slow down things considerably. Letting it do ~2500 per command in 4 commands took the 3.1 seconds listed above. Add a -n 100 to it takes 5.7 seconds, so process creation overhead is a factor here. > > etc. > > Also I didn't notice this before, but the -300 part of "chmtime -300" > was redundant before then? I.e. you're implicitly changing it to "=+0" > instead with your "touch" helper, are you not? > Right. I'm changing it to the current time. Jeff