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

[Junio C Hamano <gitster@pobox.com>]

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> 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

Thanks, both.  This indeed is a good update.

>
>>
>>  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
>>
>>