Re: [PATCH] refs.c: add a function to sort a ref list, rather then sorting on add

On Tue, 17 Apr 2007, Julian Phillips wrote:

Rather than sorting the refs list while building it, sort in one go
after it is built using a merge sort.  This has a large performance
boost with large numbers of refs.

Signed-off-by: Julian Phillips <redacted>
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Having got builtin fetch to the point of generating a correct FETCH_HEAD (for a certain path through the code at least), I revisted the speed issue I brought up a while back with the sorting of refs.

Running fetch (builtin version) on a repo with >9000 refs which is up-to-date, using the old sort-on-add I get (best of 5, warm cache):

real    0m4.351s
user    0m4.068s
sys     0m0.219s

With this patch the same fetch gives (worst of 5, warm cache):

real    0m2.196s
user    0m1.870s
sys     0m0.212s

Since this is orthogonal to making fetch a builtin, I don't see that it needs to wait ...

In case anyone is curious, doing the same fetch with master 
(v1.5.1.1-135-gf948792):

master (best of 5, warm cache):
real    0m33.962s
user    0m23.992s
sys     0m9.986s

master + patch (worst of 5, warm cache):
real    0m20.821s
user    0m10.390s
sys     0m9.799s

-- 
Julian

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NANCY!!  Why is everything RED?!