On Wed, Jan 29, 2020 at 10:03:42PM +0000, Elijah Newren via GitGitGadget wrote:
> Part of the tension noted above is that the treatment of a directory can
> changed based on the files within it, and based on the various settings
s/changed/change/, or perhaps s/changed/be changed/ ?
> Since dir.c is somewhat complex, extra cruft built up around this over
> time. While trying to unravel it, I noticed several instances where the
> first call to read_directory_recursive() would return e.g.
> path_untracked for a some directory and a later one would return e.g.
s/for a some/for some/
> However, on the positive side, it does make the code much faster. For
> the following simple shell loop in an empty repository:
>
> for depth in $(seq 10 25)
> do
> dirs=$(for i in $(seq 1 $depth) ; do printf 'dir/' ; done)
> rm -rf dir
> mkdir -p $dirs
> >$dirs/untracked-file
> /usr/bin/time --format="$depth: %e" git status --ignored >/dev/null
> done
>
> I saw the following timings, in seconds (note that the numbers are a
> little noisy from run-to-run, but the trend is very clear with every
> run):
>
> 10: 0.03
> 11: 0.05
> 12: 0.08
> 13: 0.19
> 14: 0.29
> 15: 0.50
> 16: 1.05
> 17: 2.11
> 18: 4.11
> 19: 8.60
> 20: 17.55
> 21: 33.87
> 22: 68.71
> 23: 140.05
> 24: 274.45
> 25: 551.15
>
> After this fix, those drop to:
>
> 10: 0.00
> 11: 0.00
> 12: 0.00
> 13: 0.00
> 14: 0.00
> 15: 0.00
> 16: 0.00
> 17: 0.00
> 18: 0.00
> 19: 0.00
> 20: 0.00
> 21: 0.00
> 22: 0.00
> 23: 0.00
> 24: 0.00
> 25: 0.00
I agree with Derrick here: if you just said that all these report
0.00, I would have taken your word for it.
Having said that... I don't know how to get more decimal places out
of /use/bin/time, but our trace performance facility uses nanosecond
resolution timestamps. So using this command in the loop above:
GIT_TRACE_PERFORMANCE=2 git status --ignored 2>&1 >/dev/null |
sed -n -e "s/.* performance: \(.*\): git command.*/$depth: \1/p"
gave me this:
1: 0.000574302 s
2: 0.000584995 s
3: 0.000608684 s
4: 0.000951336 s
5: 0.000762019 s
6: 0.000816685 s
7: 0.000672516 s
8: 0.000912628 s
9: 0.000661538 s
10: 0.000687465 s
11: 0.000708880 s
12: 0.000693754 s
13: 0.000726120 s
14: 0.000737334 s
15: 0.000787362 s
16: 0.000856687 s
17: 0.000780892 s
18: 0.000790798 s
19: 0.000834411 s
20: 0.000859094 s
21: 0.001230912 s
22: 0.001048852 s
23: 0.000891057 s
24: 0.000934097 s
25: 0.001051704 s
Not sure it's worth including, though.
