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Re: [QGIT PATCH/RFC]

From
MCMarco Costalba <mcostalba@gmail.com>
Date
Nov 5, 2009, 20:25 UTC
Message-ID
<e5bfff550911051225s13c6e39dh355dc3ab1c0623f@mail.gmail.com>
In-Reply-To
<4AF2AAFD.9000309@lyx.org>
On Thu, Nov 5, 2009 at 11:37, Abdelrazak Younes <younes@lyx.org> wrote:
>
> I recompiled qgit with the Qt version and I didn't notice any performance
> problem with a big repo (Qt).
>

In git we don't need to compute hashes of sha strings because they are already hashed !

That's the idea of using a custom hashing function that does nothing but taking the first chars of the sha string. Instead the general purpose Qt hashing must do real work because it has to work for any string.

When I tested I _found_ a speed difference, but now I don't remember of how much. Be sure you have warm cache when doing the test (press F5) for few times to be sure all is in RAM.

> Just tell me if this is not interesting to you and I'll shut up :-)
>
No, it is very interesting indeed. My bad I have no time for  net access today.

If QByteArray is faster then QLatin1String() we should definitely change. But if I don't remember wrong QLatin1String() is already implemented above a QByteArray and the methods that we use are inherited directly from a QByteArray, but I may be wrong. I don't have access to the sources now. I only remember that when I implemented that part it took a good amount of time and testing ;-)

Thanks Marco

Previous: Abdelrazak YounesNext: Marco Costalba
Message 7 of 10 in “[QGIT PATCH/RFC]”
  1. Abdelrazak Younes, Nov 4, 2009
  2. Marco CostalbaNov 5, 2009
  3. Abdelrazak YounesNov 5, 2009
  4. Abdelrazak YounesNov 5, 2009
  5. Abdelrazak YounesNov 5, 2009
  6. Abdelrazak YounesNov 5, 2009
  7. Marco CostalbaNov 5, 2009
  8. Marco CostalbaNov 5, 2009
  9. Abdelrazak YounesNov 6, 2009
  10. Abdelrazak YounesNov 6, 2009

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