Re: [PATCH] Improving performance with pthreads in refresh_index().

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Okay. It seems like my idea was already implemented by Linus. I wasn't aware of that fact.

Anyway, I've learned a bit more about git's bowels. Thanks a lot.

Simon

On 11.10.2011, at 13:50, Michael J Gruber wrote:

> klinkert@xxxxxxxxxx venit, vidit, dixit 11.10.2011 11:32:
>> Git performs for every file in a repository at least one (with a cold cache)
>> lstat(). In larger repositories operations like git status take a
>> long time. In case your local repository is located on a remote server
>> (e. g. mounted via nfs) it ends up in an *incredible* slow git.
>> 
>> With this patch you're able to determine a number of threads (maxthreads)
>> in your config file to run these tons of lstats in threads. There
>> won't be created any pthreads if you haven't set maxthreads. In my
>> test cases a git status with this patch performs enormously faster (over
>> two minutes before and approximately 25 seconds now). Of course, it
>> has a positive impact on other git commands, too.
> 
> Can you specify under which circumstances one should get a speedup? Our
> NFS isn't slow enough... but on a dead slow sshfs work tree I get the
> following for "git status -s":
> 
> maxthreads: 0, preloadindex: false, time: 14.73
> maxthreads: 1, preloadindex: false, time: 14.25
> maxthreads: 2, preloadindex: false, time: 13.32
> maxthreads: 3, preloadindex: false, time: 12.40
> maxthreads: 4, preloadindex: false, time: 12.65
> maxthreads: 5, preloadindex: false, time: 12.16
> maxthreads: 8, preloadindex: false, time: 12.32
> maxthreads: 10, preloadindex: false, time: 11.98
> maxthreads: 15, preloadindex: false, time: 12.31
> maxthreads: 20, preloadindex: false, time: 12.00
> maxthreads: 0, preloadindex: true, time: 12.17
> maxthreads: 1, preloadindex: true, time: 11.98
> maxthreads: 2, preloadindex: true, time: 12.21
> maxthreads: 3, preloadindex: true, time: 11.99
> maxthreads: 4, preloadindex: true, time: 12.14
> maxthreads: 5, preloadindex: true, time: 12.21
> maxthreads: 8, preloadindex: true, time: 12.14
> maxthreads: 10, preloadindex: true, time: 12.08
> maxthreads: 15, preloadindex: true, time: 12.16
> maxthreads: 20, preloadindex: true, time: 11.96
> 
> So it seams it gives me what preloadindex does, which is not much.
> 
> Note: I'm not saying the patch is bad. I'm just wondering whether that
> is expected.
> 
> Michael
> P.S.: It's actually sshfs with ssh to an NFSv3 client (server restricts
> exports) :(
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