From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Clemens Buchacher <drizzd@gmx.net>,
Manlio Perillo <manlio.perillo@gmail.com>
Cc: "SZEDER Gábor" <szeder.dev@gmail.com>,
git@vger.kernel.org, manlio.perillo@gmail.com, gitster@pobox.com
Subject: Re: [PATCH] completion: improve ls-files filter performance
Date: Wed, 4 Apr 2018 18:16:13 +0200 (DST) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1804041805150.55@ZVAVAG-6OXH6DA.rhebcr.pbec.zvpebfbsg.pbz> (raw)
In-Reply-To: <20180404074658.GA5833@Sonnenschein.localdomain>
Hi drizzd,
On Wed, 4 Apr 2018, Clemens Buchacher wrote:
> From the output of ls-files, we remove all but the leftmost path
> component and then we eliminate duplicates. We do this in a while loop,
> which is a performance bottleneck when the number of iterations is large
> (e.g. for 60000 files in linux.git).
>
> $ COMP_WORDS=(git status -- ar) COMP_CWORD=3; time _git
>
> real 0m11.876s
> user 0m4.685s
> sys 0m6.808s
>
> Replacing the loop with the cut command improves performance
> significantly:
>
> $ COMP_WORDS=(git status -- ar) COMP_CWORD=3; time _git
>
> real 0m1.372s
> user 0m0.263s
> sys 0m0.167s
>
> The measurements were done with Msys2 bash, which is used by Git for
> Windows.
Those are nice numbers right there, so I am eager to get this into Git for
Windows as quickly as it stabilizes (i.e. when it hits `next` or so).
I was wondering about one thing, though:
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 6da95b8..69a2d41 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -384,12 +384,7 @@ __git_index_files ()
> local root="${2-.}" file
>
> __git_ls_files_helper "$root" "$1" |
> - while read -r file; do
> - case "$file" in
> - ?*/*) echo "${file%%/*}" ;;
This is a bit different from the `cut -f1 -d/` logic, as it does *not
necessarily* strip a leading slash: for `/abc` the existing code would
return the string unmodified, for `/abc/def` it would return an empty
string!
Now, I think that this peculiar behavior is most likely bogus as `git
ls-files` outputs only relative paths (that I know of). In any case,
reducing paths to an empty string seems fishy.
I looked through the history of that code and tracked it all the way back
to
https://public-inbox.org/git/1357930123-26310-1-git-send-email-manlio.perillo@gmail.com/
(that is the reason why you are Cc:ed, Manlio). Manlio, do you remember
why you put the `?` in front of `?*/*` here? I know, it's been more than
five years...
Out of curiosity, would the numbers change a lot if you replaced the `cut
-f1 -d/` call by a `sed -e 's/^\//' -e 's/\/.*//'` one?
I am not proposing to change the patch, though, because we really do not
need to expect `ls-files` to print lines with leading slashes.
> - *) echo "$file" ;;
> - esac
> - done | sort | uniq
> + cut -f1 -d/ | sort | uniq
> }
>
> # Lists branches from the local repository.
Ciao,
Dscho
next prev parent reply other threads:[~2018-04-04 16:16 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-17 8:17 [PATCH 1/2] completion: improve ls-files filter performance Clemens Buchacher
2018-03-17 8:17 ` [PATCH 2/2] completion: simplify ls-files filter Clemens Buchacher
2018-03-18 0:16 ` Junio C Hamano
2018-03-18 1:26 ` SZEDER Gábor
2018-03-18 5:28 ` Junio C Hamano
2018-04-04 7:46 ` [PATCH] completion: improve ls-files filter performance Clemens Buchacher
2018-04-04 16:16 ` Johannes Schindelin [this message]
2018-04-16 22:41 ` [PATCH 00/11] completion: path completion improvements: speedup and quoted paths SZEDER Gábor
2018-04-16 22:41 ` [PATCH 01/11] t9902-completion: add tests demonstrating issues with quoted pathnames SZEDER Gábor
2018-04-17 3:48 ` Junio C Hamano
2018-04-17 23:32 ` SZEDER Gábor
2018-04-17 23:41 ` SZEDER Gábor
2018-04-18 1:22 ` Junio C Hamano
2018-04-26 0:25 ` SZEDER Gábor
2018-04-26 2:11 ` Junio C Hamano
2018-05-18 14:17 ` [PATCH 0/2] Test improvements for 'sg/complete-paths' SZEDER Gábor
2018-05-18 14:17 ` [PATCH 1/2] completion: don't return with error from __gitcomp_file_direct() SZEDER Gábor
2018-05-18 14:17 ` [PATCH 2/2] t9902-completion: exercise __git_complete_index_file() directly SZEDER Gábor
2018-05-18 19:25 ` Eric Sunshine
2018-05-21 12:14 ` Johannes Schindelin
2018-05-21 11:35 ` [PATCH 0/2] Test improvements for 'sg/complete-paths' Johannes Schindelin
2018-05-21 12:17 ` Johannes Schindelin
2018-04-18 12:31 ` [PATCH 01/11] t9902-completion: add tests demonstrating issues with quoted pathnames Johannes Schindelin
2018-04-19 19:08 ` SZEDER Gábor
2018-04-16 22:41 ` [PATCH 02/11] completion: move __git_complete_index_file() next to its helpers SZEDER Gábor
2018-04-16 22:41 ` [PATCH 03/11] completion: simplify prefix path component handling during path completion SZEDER Gábor
2018-04-16 22:41 ` [PATCH 04/11] completion: support completing non-ASCII pathnames SZEDER Gábor
2018-04-16 22:41 ` [PATCH 05/11] completion: improve handling quoted paths on the command line SZEDER Gábor
2018-04-16 22:41 ` [PATCH 06/11] completion: let 'ls-files' and 'diff-index' filter matching paths SZEDER Gábor
2018-04-16 22:41 ` [PATCH 07/11] completion: use 'awk' to strip trailing path components SZEDER Gábor
2018-04-16 22:41 ` [PATCH 08/11] t9902-completion: ignore COMPREPLY element order in some tests SZEDER Gábor
2018-04-16 22:41 ` [PATCH 09/11] completion: remove repeated dirnames with 'awk' during path completion SZEDER Gábor
2018-04-16 22:42 ` [PATCH 10/11] completion: improve handling quoted paths in 'git ls-files's output SZEDER Gábor
2018-04-16 22:42 ` [PATCH 11/11] completion: fill COMPREPLY directly when completing paths SZEDER Gábor
2018-03-18 0:13 ` [PATCH 1/2] completion: improve ls-files filter performance Junio C Hamano
2018-03-19 17:12 ` Johannes Schindelin
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