Re: [PATCH 09/16] documentation: add documentation for the bitmap format

From: Jeff King <peff@peff.net>
Date: Jun 27, 2013, 02:45 UTC
Message-ID: <20130627024521.GA6936@sigill.intra.peff.net>
In-Reply-To: <CAFFjANSr2QRLE8DSPP2zZ_baEZUqR8dzkPzMwqyEqgFX=8cnog@mail.gmail.com>

On Thu, Jun 27, 2013 at 04:36:54AM +0200, Vicent Martí wrote:

> That was a very rude reply. :(
> 
> Please refrain from interacting with me in the ML in the future. I'l
> do accordingly.

I agree that the pointer arithmetic thing may have been a little much, but I think there are some points we need to address in Shawn's email.

In particular, it seems like the slowness we saw with the v1 bitmap format is not what Shawn and Colby have experienced. So it's possible that our test setup is bad or different. Or maybe the C v1 reading implementation had some problems that are fixable. It's hard to say because we haven't shown any code that can be timed and compared.

And the pack-order versus idx-order for the bitmaps is still up in the air. Do we have numbers on the on-disk sizes of the resulting EWAHs? The pack-order ones should be more amenable to run-length encoding, especially as you get further down into history (the tip ones would mostly be 1's, no matter how you order them).

-Peff