Re: git cherry improvements suggestions

From: Piotr Krukowiecki <piotr.krukowiecki@gmail.com>
Date: Mar 24, 2011, 07:40 UTC
Message-ID: <AANLkTi=7NKn4FrCqFaGH+XTHRw3oLCv=aKPWAJfNsgD_@mail.gmail.com>
In-Reply-To: <AANLkTi=7=QDh0Pe9W4bRcGY5Krg7sBqRcZ2C1YonJSRN@mail.gmail.com>

On Wed, Mar 23, 2011 at 8:28 PM, Piotr Krukowiecki <piotr.krukowiecki@gmail.com> wrote:

Show 56 quoted lines

> On Wed, Mar 23, 2011 at 3:44 PM, Michael J Gruber
> <git@drmicha.warpmail.net> wrote:
>> Piotr Krukowiecki venit, vidit, dixit 23.03.2011 15:43:
>>> On Wed, Mar 23, 2011 at 2:33 PM, Michael J Gruber
>>> <git@drmicha.warpmail.net> wrote:
>>>> Piotr Krukowiecki venit, vidit, dixit 23.03.2011 14:23:
>>>>> Just some stats:
>>>>>
>>>>>    git log --cherry-mark --left-right --oneline --date-order branch...trunk
>>>>>
>>>>> lists 1004 commits, takes about 20s and memory peaks to about 670MB
>>>>> twice during the run (I'm on linux with AMD Phenom II X4 945)
>>>>>
>>>>> With limit it prints X last commits (the limiting seems to take place after all
>>>>> work, on the output list only).
>>>>>
>>>>> branch..trunk is 551 commits, the other way is 453 commits.
>>>>> 710 commits are found to be "=", 98 "<", 196 ">".
>>>>>
>>>>> Note, I'm not saying it's too slow, or that it's working incorrectly, I'm just
>>>>> giving real-life stats if anyone was interested.
>>>>> I suspect such checks won't be done frequently.
>>>>
>>>> You don't need to say it's slow - I've said so already :(
>>>>
>>>> http://permalink.gmane.org/gmane.comp.version-control.git/169725
>>>
>>> In the link above:
>>>   git cherry A B: 0.4s
>>>   git rev-list --cherry A...B: 1.7s
>>>
>>> So rev-list is 4.25x slower.
>>>
>>> In my case it's only 1.23x slower:
>>>
>>>    $ time git rev-list --cherry branch...trunk  > /tmp/rev-list
>>>    real       0m18.627s
>>>    user       0m17.710s
>>>    sys        0m0.900s
>>>
>>>    $ time git cherry  branch trunk  > /tmp/cherry
>>>    real       0m15.345s
>>>    user       0m14.310s
>>>    sys        0m1.020s
>>>
>>>
>>
>> How's that with > /dev/null (or with --count for rev-list)? Also, how
>> many merge bases do you have:
>>
>> git merge-base --all branch trunk | wc -l
>
> I expect only one - there should be no merges between those two
> branches.
>
> I will do measurements tomorrow.

Branches might change a bit since yesterday so the exact numbers might be a bit different.

$ time git cherry  branch trunk  > /dev/null

real 0m15.246s user 0m14.260s sys 0m0.970s

$ time git rev-list --cherry branch...trunk  > /dev/null

real 0m18.801s user 0m17.980s sys 0m0.800s

$ time git rev-list --cherry --count branch...trunk 556

real 0m18.825s user 0m18.010s sys 0m0.770s

$ time git merge-base --all branch trunk | wc -l 2

real 0m0.538s user 0m0.490s sys 0m0.040s

I expected one merge base, but it appears our history is seriously fscked, either by past svn operations or by git-svn clone :)

(I'm not saying there's an error somewhere, just that the history is ... complicated)

-- 
Piotr Krukowiecki