Re: [PATCH] low performance of lib/sort.c , kernel 2.6.18
From: Zou Nan hai
Date: Thu Sep 28 2006 - 20:24:21 EST
On Fri, 2006-09-29 at 06:33, Matt Mackall wrote:
> On Thu, Sep 28, 2006 at 11:18:45PM +0800, keios wrote:
> > It is a non-standard heap-sort algorithm implementation because the
> > index of child node is wrong . The sort function still outputs right
> > result, but the performance is O( n * ( log(n) + 1 ) ) , about 10% ~
> > 20% worse than standard algorithm .
> > Signed-off-by: keios <keios.cn@xxxxxxxxx>
> Was a bit mystified by this as your patch matches what I've got
> in my userspace test harness from 2003.
> Here's what I submitted, which is almost the same as yours:
> Then Zou Nan hai sent Andrew a fix for an off-by-one bug here (merged
> with my patch):
> ..which introduced the performance regression.
> And then I subsequently tweaked my local copy for use in another
> project, coming up with your version.
> So this passes my test harness just fine (for both even and odd array
> Acked-by: Matt Mackall <mpm@xxxxxxxxxxx>
I think this patch is correct.
Zou Nan hai
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