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Re: [PATCH] Speed-up of libsvn_diff by reworking fp argument

From: Stefan Fuhrmann <eqfox_at_web.de>
Date: Sun, 29 May 2011 15:46:48 +0200

On 27.05.2011 20:41, Morten Kloster wrote:
> [[[
> Faster LCS algorithm in libsvn_diff by reworking fp argument
> * subversion/libsvn_diff/lcs.c
> (svn_diff__snake): fp and k arguments are added by caller
> ]]]
> Calling svn_diff__snake with fp+k as argument instead of both as
> separate arguments reduces running time for the lcs algorithm
> substantially; by more than 20% on my system. Combining this
> patch with the idx one gives a slight additional speed
> improvement, but not nearly the sum of each separate
> improvement (on my system, at least).
Hi Morten,

Did you activate compiler optimizations (e.g. use the release build in VS)?

While your patch makes the code easier to read, the GCC output is
the same as for the unchanged code - except for an additional NOP
to ensure optiminal branch target alignment.

-- Stefan^2.
Received on 2011-05-29 15:47:23 CEST

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