Re: [GSoC] Git Blog 11

From: ZheNing Hu <adlternative@gmail.com>
Date: Aug 3, 2021, 02:37 UTC
Message-ID: <CAOLTT8SaXqWF3AJssqudrDK-KZN3oESO7Xh0JTYB_=HR9L9sHg@mail.gmail.com>
In-Reply-To: <CAP8UFD16pqERdF4Mdq=_ktvFB1rcXwB9PRy8TjNq=ThH5HbeqA@mail.gmail.com>

Christian Couder <christian.couder@gmail.com> 于2021年8月2日周一 下午2:25写道：

Show 25 quoted lines

>
> On Sun, Aug 1, 2021 at 8:45 AM ZheNing Hu <adlternative@gmail.com> wrote:
>
> > in some cases, this is the result of the performance test of
> > `t/perf/p1006-cat-file.sh`:
> >
> > ```
> > Test                                        HEAD~             HEAD
> > ------------------------------------------------------------------------------------
> > 1006.2: cat-file --batch-check              0.10(0.09+0.00)
> > 0.11(0.10+0.00) +10.0%
> > 1006.3: cat-file --batch-check with atoms   0.09(0.08+0.01)
> > 0.09(0.06+0.03) +0.0%
> > 1006.4: cat-file --batch                    0.62(0.58+0.04)
> > 0.57(0.54+0.03) -8.1%
> > 1006.5: cat-file --batch with atoms         0.63(0.60+0.02)
> > 0.52(0.49+0.02) -17.5%
> > ```
> >
> > We can see that the performance of `git cat-file --batch` has been a
> > certain improvement!
>
> Yeah, sure -8.1% or -17.5% is really nice! But why +10.0% for
> `cat-file --batch-check`?
>

I think it's not very important. Because our optimization is skipping parse_object_buffer(), git cat-file --batch-check will not set oi->contentp by default, parse_object_buffer() will not be executed, Therefore, we did not optimize `git cat-file --batch-check` at all. 10% may be small enough for git cat-file --batch-check. The noise of environment even will cover it...

Show 12 quoted lines

> > Tell a joke: removing 1984531500 if checking can reduce the startup
> > time of GTA5 by 70%. :-D
>
> s/if checking/checks/
>
> As this joke refers to:
>
> https://rockstarintel.com/a-fan-reduces-gta-online-loading-times-by-70
>
> it might be nice to add a link to help people like me who didn't know
> about this and had to google it.
>

Ehhh, makes sense.

> > Currently the patch has not been submitted to the mailing list, let us
> > wait a bit...
>
> Looking forward to it...

I am afraid we need to wait until ref-filter-raw-data merged into master.

The preview version is here: https://github.com/adlternative/git/commit/6fcf51c4b1cbb510dac775a6fbf3db361bc1c327

Thanks. -- ZheNing Hu