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Re: update-index --assume-unchanged doesn't make things go fast

From
Michael J Gruber <michaeljgruber+gmane@fastmail.fm>
Date
Jun 26, 2008, 08:47 UTC
Message-ID
<g3vl2l$qn7$1@ger.gmane.org>
In-Reply-To
<32541b130806251102l6e71a050o82fbd4f272d1d23f@mail.gmail.com>
Avery Pennarun venit, vidit, dixit 25.06.2008 20:02:
Show 19 quoted lines
> On 6/25/08, Michael J Gruber <michaeljgruber+gmane@fastmail.fm> wrote:
>>> 4) My idea is to eventually --assume-unchanged my whole repository,
>>> then write a cheesy daemon that uses the Win32 dnotify-equivalent to
>>> watch for files that get updated and then selectively
>>> --no-assume-unchanged files that it gets notified about.  That would
>>> avoid the need to ever synchronously scan the whole repo for changes,
>>> thus making my git-Win32 experience much faster and more enjoyable.
>>> (This daemon ought to be possible to run on Linux as well, for similar
>>> improvements on gigantic repositories.  Also note that TortoiseSVN for
>>> Windows does something similar to track file status updates, so this
>>> isn't *just* me being crazy.)
>>  Looks like users on slow NFS would profit, too. Hate to say it, but hg
>> feels faster on (slow) NFS than git. Yet I use git, for other reasons ;)
> 
> Hmm, can you do dnotify over NFS?
> 
> I'd like to know how hg goes any faster.  As far as I can see, git is
> going as fast as can be without some kind of daemon or other magic.
> (Except for my point #3, which seems relatively minor.)

I haven't done any measurements, maybe I should; getting consistent results would require setting up an isolated NFS environment, though.

The thing is that hg is very careful about serializing and minimizing disk I/O, whereas git is very clever about delegating stuff to the kernel and processing data efficiently. In my work environment I have to keep my repos on NFS. For heavy history rewriting I resort to /tmp or /dev/shm temporarily. But git status is kinda slow on NFS. I don't know about [di]?notify over NFS.

Michael
Previous: Avery PennarunNext: Jakub Narebski
Message 4 of 16 in “update-index --assume-unchanged doesn't make things go fast”
  1. Avery PennarunJun 25, 2008
  2. Michael J GruberJun 25, 2008
  3. Avery PennarunJun 25, 2008
  4. Michael J GruberJun 26, 2008
  5. Jakub NarebskiJun 25, 2008
  6. Junio C HamanoJun 25, 2008
  7. Avery PennarunJun 25, 2008
  8. Jakub NarebskiJun 25, 2008
  9. Avery PennarunJun 26, 2008
  10. Stephen R. van den BergJun 26, 2008
  11. Avery PennarunJun 27, 2008
  12. Jakub NarebskiJun 27, 2008
  13. Avery PennarunJun 27, 2008
  14. Dana HowJun 27, 2008
  15. Avery PennarunJun 27, 2008
  16. Junio C HamanoJun 28, 2008

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