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From: ZheNing Hu <adlternative@gmail.com>
To: Jeff King <peff@peff.net>
Cc: "Git List" <git@vger.kernel.org>,
	"Junio C Hamano" <gitster@pobox.com>,
	"Christian Couder" <christian.couder@gmail.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH 2/2] ref-filter: implement "quick" formats
Date: Mon, 6 Sep 2021 21:34:56 +0800	[thread overview]
Message-ID: <CAOLTT8QqLXdvL5Y8OkEzuctGgnDHA1DQu8ZaxQGnfHPBqNVm4g@mail.gmail.com> (raw)
In-Reply-To: <YTTBCWlsC1cBZMio@coredump.intra.peff.net>

Jeff King <peff@peff.net> 于2021年9月5日周日 下午9:07写道:
>
> On Sun, Sep 05, 2021 at 04:20:07PM +0800, ZheNing Hu wrote:
>
> > > +       case REF_FORMAT_QUICK_OBJECTNAME_REFNAME:
> > > +               printf("%s %s\n", oid_to_hex(oid), refname);
> > > +               return 0;
> > > +       }
> > > +       BUG("unknown ref_format_quick value: %d", format->quick);
> > > +}
> > > +
> >
> > So as a fast path, we actually avoided format_ref_array_item() when we are using
> > %(objectname) and %(refname). But the problem is that it’s not very elegant
> > (using string compare), and it is no optimization for other atoms that
> > require in-depth
> > parsing. I remember the "fast path" used by Ævar last time, and it
> > seems that Junio doesn't
> > like them. [1][2]
>
> Yes, I did say it was "pretty horrible". :)
>
> It was mostly meant as a proof-of-concept to see where the time was
> going, and what was possible. It _could_ be used as a stop-gap while
> improving the general performance, but it's gross enough that it's
> probably not a good idea (it's increased maintenance, but also it
> dis-incentivizes fixing the real problems).
>

Agree. Like you said, these performance gaps are caused by the used_atom
system.

> -Peff

Thanks.
--
ZheNing Hu

  reply	other threads:[~2021-09-06 13:35 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-04 12:40 [hacky PATCH 0/2] speeding up trivial for-each-ref invocations Jeff King
2021-09-04 12:41 ` [PATCH 1/2] ref-filter: hacky "streaming" mode Jeff King
2021-09-05  8:20   ` ZheNing Hu
2021-09-05 13:04     ` Jeff King
2021-09-07  5:28       ` ZheNing Hu
2021-09-07 18:01         ` Jeff King
2021-09-09 14:45           ` ZheNing Hu
2021-09-10 14:26             ` Jeff King
2021-09-15 12:27               ` ZheNing Hu
2021-09-15 14:23                 ` ZheNing Hu
2021-09-16 21:45                   ` Jeff King
2021-09-20  7:42                     ` ZheNing Hu
2021-09-16 21:31                 ` Jeff King
2021-09-05 13:15     ` Jeff King
2021-09-07  5:42       ` ZheNing Hu
2021-09-04 12:42 ` [PATCH 2/2] ref-filter: implement "quick" formats Jeff King
2021-09-05  8:20   ` ZheNing Hu
2021-09-05 13:07     ` Jeff King
2021-09-06 13:34       ` ZheNing Hu [this message]
2021-09-07 20:06       ` Junio C Hamano
2021-09-05  8:19 ` [hacky PATCH 0/2] speeding up trivial for-each-ref invocations ZheNing Hu
2021-09-05 12:49   ` Jeff King
2021-09-06 13:30     ` ZheNing Hu
2021-09-07 17:28       ` Jeff King
2021-09-09 13:20         ` ZheNing Hu
2021-09-06  6:54 ` Patrick Steinhardt

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