Re: [PATCH] xdiff: optimise for no whitespace difference when ignoring whitespace.
Dylan Reid <dgreid@gmail.com> writes:
> In xdl_recmatch, do the memcmp to check if the two lines are equal before
> checking if whitespace flags are set. If the lines are identicle, then
> there is no need to check if they differ only in whitespace.
> This makes the common case (there is no whitespace difference) faster.
> It costs the case where lines are the same length and contain
> whitespace differences, but the common case is more than 20% faster.
"more than 20% faster" based on what dataset and benchmark?
Show 29 quoted lines
>
> Signed-off-by: Dylan Reid <dgreid@gmail.com>
> ---
> xdiff/xutils.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/xdiff/xutils.c b/xdiff/xutils.c
> index bc12f29..22f9bd6 100644
> --- a/xdiff/xutils.c
> +++ b/xdiff/xutils.c
> @@ -190,8 +190,10 @@ int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
> {
> int i1, i2;
>
> + if (s1 == s2 && !memcmp(l1, l2, s1))
> + return 1;
> if (!(flags & XDF_WHITESPACE_FLAGS))
> - return s1 == s2 && !memcmp(l1, l2, s1);
> + return 0;
>
> i1 = 0;
> i2 = 0;
> --
> 1.7.1
>
> --
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> More majordomo info at http://vger.kernel.org/majordomo-info.htmlJunio C Hamano <gitster@pobox.com>