Re: [PATCH] [GSOC] ref-filter: use single strbuf for all output

>
> On 4/5/2021 10:01 AM, ZheNing Hu via GitGitGadget wrote:
> > From: ZheNing Hu <adlternative@gmail.com>
> >
> > When we use `git for-each-ref`, every ref will call
> > `show_ref_array_item()` and allocate its own final strbuf
> > and error strbuf. Instead, we can provide two single strbuf:
> > final_buf and error_buf that get reused for each output.
>
> s/two single strbuf/two buffers/
>
> > When run it 100 times:
> >
> > $ git for-each-ref
> >
> > on git.git :
> >
> > 3.19s user
> > 3.88s system
> > 35% cpu
> > 20.199 total
> >
> > to:
> >
> > 2.89s user
> > 4.00s system
> > 34% cpu
> > 19.741 total
> >
> > The performance has been slightly improved.
>
> This is a nice amount of time! Perhaps simplify the
> presentation:
>

>   The performance for 'git for-each-ref' on the Git
>   repository itself with X references changes from
>   3.2 seconds to 2.9 seconds.
>
> > Signed-off-by: ZheNing Hu <adlternative@gmail.com>
> > ---
> >     [GSOC] ref-filter: use single strbuf for all output
> >
> >     This patch learned Jeff King's optimization measures in git
> >     cat-file(79ed0a5): using a single strbuf for all objects output Instead
> >     of allocating a large number of small strbuf for every object.
>
> This part of the cover letter could be put into the
> commit message itself. Use the correct formatting,
> though:
>
>   This approach is similar to the one used by 79ed0a5
>   (cat-file: use a single strbuf for all output, 2018-08-14)
>   to speed up the cat-file builtin.
>