Re: [PATCH v2 17/16] t3427: accelerate this test by using fast-export and fast-import

From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Elijah Newren <newren@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [PATCH v2 17/16] t3427: accelerate this test by using fast-export and fast-import
Date: Mon, 9 Sep 2019 22:29:30 +0200 (CEST)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.1909092229040.5377@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20190904214048.29331-1-newren@gmail.com>

Hi Elijah,

On Wed, 4 Sep 2019, Elijah Newren wrote:

> fast-export and fast-import can easily handle the simple rewrite that
> was being done by filter-branch, and should be faster on systems with a
> slow fork.  Measuring the overall time taken for all of t3427 (not just
> the difference between filter-branch and fast-export/fast-import) shows
> a speedup of about 5% on Linux and 11% on Mac.
>
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
> This patch is meant to be added onto the end of js/rebase-r-strategy; an
> earlier version of this patch conflicted js/rebase-r-strategy so now I'm
> basing on top of that series.  The speedup is also less impressive now
> that there is only one filter-branch invocation being replaced instead of
> a handful.  Still a nice speedup, though.

ACK!

Thanks,
Dscho

>
>  t/t3427-rebase-subtree.sh | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/t/t3427-rebase-subtree.sh b/t/t3427-rebase-subtree.sh
> index 39e348de16..bec48e6a1f 100755
> --- a/t/t3427-rebase-subtree.sh
> +++ b/t/t3427-rebase-subtree.sh
> @@ -59,7 +59,10 @@ test_expect_success 'setup' '
>  	test_commit files_subtree/master5 &&
>
>  	git checkout -b to-rebase &&
> -	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
> +	git fast-export --no-data HEAD -- files_subtree/ |
> +		sed -e "s%\([0-9a-f]\{40\} \)files_subtree/%\1%" |
> +		git fast-import --force --quiet &&
> +	git reset --hard &&
>  	git commit -m "Empty commit" --allow-empty
>  '
>
> --
> 2.22.0.19.ga495766805
>
>