"Shawn O. Pearce" <spearce@xxxxxxxxxxx> wrote:
> Johannes Schindelin <Johannes.Schindelin@xxxxxx> wrote:
> > -- snipsnap --
> > [PATCH] xdiff/xutils.c(xdl_hash_record): factor out whitespace handling
...
> > ---
> >
> > Please do not consider this patch _unless_ it is proven to enhance
> > the profile statistics substantially.
>
> This is a massive difference for me.
...
> # stock v1.5.1-rc1
> $ for a in 1 2 3 4 5;do /usr/bin/time ../lt-blame blame --incremental HEAD git-gui.sh >/dev/null;done
> 6.27 real 5.31 user 0.55 sys
> 6.40 real 5.32 user 0.55 sys
> 6.33 real 5.33 user 0.53 sys
> 6.67 real 5.32 user 0.55 sys
> 6.18 real 5.31 user 0.53 sys
>
> # with the above patch
> $ for a in 1 2 3 4 5;do /usr/bin/time ../js-blame blame --incremental HEAD git-gui.sh >/dev/null;done
> 3.57 real 2.87 user 0.51 sys
> 3.58 real 2.87 user 0.51 sys
> 3.53 real 2.86 user 0.52 sys
> 3.61 real 2.86 user 0.51 sys
> 3.64 real 2.87 user 0.52 sys
DrNick suggested on #git to try flipping the isspace test around.
This is a smaller change and generated the same ~3.60 seconds run
as Dscho's patch. I like DrNick's version better. ;-)
-->8--
[PATCH] xdiff/xutils.c(xdl_hash_record): factor out whitespace handling
Since in at least one use case, xdl_hash_record() takes over 15%
of the CPU time, it makes sense to even micro-optimize it. For
many cases, no whitespace special handling is needed, and in these
cases we should not even bother to check for whitespace in _every_
iteration of the loop.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@xxxxxx>
Signed-off-by: Shawn O. Pearce <spearce@xxxxxxxxxxx>
---
xdiff/xutils.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index 3653864..7b1f213 100644
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -241,7 +241,7 @@ unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
char const *ptr = *data;
for (; ptr < top && *ptr != '\n'; ptr++) {
- if (isspace(*ptr) && (flags & XDF_WHITESPACE_FLAGS)) {
+ if ((flags & XDF_WHITESPACE_FLAGS) && isspace(*ptr)) {
const char *ptr2 = ptr;
while (ptr + 1 < top && isspace(ptr[1])
&& ptr[1] != '\n')
--
1.5.1.rc1.595.gd1206
--
Shawn.
-
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