From: "Benjamin R. Haskell" <zsh@benizi.com>
To: zsh-workers@zsh.org
Subject: Re: [PATCH] _git: Also complete FETCH_HEAD, ORIG_HEAD and MERGE_HEAD.
Date: Mon, 29 Mar 2010 09:56:43 -0400 (EDT) [thread overview]
Message-ID: <alpine.LNX.2.01.1003230000560.19615@hp.internal> (raw)
In-Reply-To: <dbfc82861003220227i701893e8hee459c1fd72014d1@mail.gmail.com>
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[oops, sat in my drafts]
On Mon, 22 Mar 2010, Nikolai Weibull wrote:
> On Mon, Mar 22, 2010 at 03:30, Benjamin R. Haskell <zsh@benizi.com> wrote:
> > Testing the existence of $gitdir/{refname} seems a fine compromise.
> > (Really, I don't see the issue; this seems like a drop in the bucket
> > of _git's performance issues... I s'pose the forks are
> > prohibitively expensive on Win32? Revised patch below anyway.)
>
> > (In case it's unclear, I prefer my previous patch -- doesn't _git
> > fork all over the place? -- but either one's preferable to no-change
> > or always-adding-them.)
>
> Yes, it does, and, as you mention, it’s horribly slow to fork on
> Windows. I mean, what where they thinking? But I question the value
> of forking for this particular test. Still, it’s more correct to use
> rev-parse. As your patch uses rev-parse to find gitdir once already,
> we’re not gaining much by globbing instead.
>
> I just ran a benchmark on Cygwin and it takes about 0.5 seconds to run
> four rev-parses.
>
> Perhaps completing them all without checking if they’re valid
> beforehand is the best solution?
I'd still rather see some checking than none at all. (MERGE_HEAD isn't
often applicable, for example.)
In the context I was using to test:
$ git log <Tab>
It appears to be completing both tags and branches, and it already forks
git once to find each of those (@lines 3117 and 3140). Four more forks
(the version calling rev-parse on each name) might be excessive, but one
doesn't seem so bad (the version calling it once to get --git-dir) for
the added filtering.
rev-parse each: 100% correct, only much slower on Win32 (~.5s)
rev-parse dir + glob: mostly correct, a-bit-slower on Win32 (~.125s)
always-complete: usually wrong, no slower
Really, I feel like the forking cost would prohibit _git from being
useful on Win32 in the first place, so it seems an odd metric to use.
(Are there other systems where the fork is expensive? AFAIK, anything
Unix-like shouldn't incur too much cost for it, which leaves Win32 and
...?)
--
Best,
Ben
prev parent reply other threads:[~2010-03-29 14:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-21 17:23 Simon Ruderich
2010-03-21 19:48 ` Benjamin R. Haskell
2010-03-21 20:17 ` Nikolai Weibull
2010-03-22 1:25 ` Simon Ruderich
2010-03-22 2:30 ` Benjamin R. Haskell
2010-03-22 9:27 ` Nikolai Weibull
2010-03-29 0:07 ` Simon Ruderich
2010-05-01 8:28 ` Simon Ruderich
2010-05-01 10:46 ` Frank Terbeck
2010-05-01 12:12 ` Simon Ruderich
2010-05-01 12:17 ` Frank Terbeck
2010-05-01 20:32 ` Simon Ruderich
2010-05-02 9:04 ` Frank Terbeck
2010-05-03 14:51 ` Benjamin R. Haskell
2010-03-29 13:56 ` Benjamin R. Haskell [this message]
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