[MERGE] knit performance improvements

[Martin Pool]

On  3 Apr 2006, Robert Collins <robertc at robertcollins.net> wrote:
> This patch makes knits more performant in a number of ways.
> 
> It contains:
>  * A tweak to missing that I commited in here by mistake which defers
> taking write locks unless needed.
>    (I'll update that to not conflict with Aarons patch if his has been
>     merged).
>  * Various microoptimisations to knit and gzip - reducing function call 
>    counts in inner loops, reducing double-handling of data, increasing
>    knit header parsing performance, removing 'list.index' calls
>    completely etc.
>  * changes the data format of knits to remove an extraneous \n in the 
>    compressed content data, which lets it be trivially pulled into 
>    memory in a single 'readlines()' call.

Does this mean it's incompatible with any existing knits people might
have?  (It's ok if it is since it's still experimental -- I just
wanted to check.)

-- 
Martin