* [PATCH] Mild setarrvalue() optimization
@ 2016-11-08 10:27 Sebastian Gniazdowski
2016-11-08 15:46 ` Daniel Shahaf
0 siblings, 1 reply; 2+ messages in thread
From: Sebastian Gniazdowski @ 2016-11-08 10:27 UTC (permalink / raw)
To: zsh-workers
[-- Attachment #1: Type: text/plain, Size: 906 bytes --]
Hello,
there's freearray() at end of setarrvalue(). It can be replaced with
free() if ownership of all strings will be given away:
for (r = val; *r;)
*p++ = ztrdup(*r++);
becomes:
for (r = val; *r;)
*p++ = *r++;
and freearray(val) -> free(val).
It is very provable that this is correct: `val` must have data of the
same kind as ztrdup() produces, as it is simply passed to freearray(),
where zsfree() is called on each string.
Test function:
test_fun() {
local -a arr
arr=( "a" )
repeat 20; do
arr+=( $arr )
done
}
Runs 2189 ms when no optimization, 1653 ms when optimized (when ran 3
times, test script attached). This is a mild optimization as most often
short arrays are being assigned, not long like in the test function, but
still, this can save one's day in certain situations.
--
Sebastian Gniazdowski
psprint@fastmail.com
[-- Attachment #2: array_mild_opt.diff --]
[-- Type: text/plain, Size: 668 bytes --]
diff --git a/Src/params.c b/Src/params.c
index 330f22b..5a3e0d3 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2648,14 +2648,18 @@ setarrvalue(Value v, char **val)
for (i = 0; i < v->start; i++)
*p++ = i < pre_assignment_length ? ztrdup(*q++) : ztrdup("");
for (r = val; *r;)
- *p++ = ztrdup(*r++);
+ /* Give away ownership of the string */
+ *p++ = *r++;
if (v->end < pre_assignment_length)
for (q = old + v->end; *q;)
*p++ = ztrdup(*q++);
*p = NULL;
v->pm->gsu.a->setfn(v->pm, new);
- freearray(val);
+
+ /* Ownership of all strings has been
+ * given away, can plainly free */
+ free(val);
}
}
[-- Attachment #3: test1.zsh --]
[-- Type: application/octet-stream, Size: 211 bytes --]
#!/usr/local/bin/zsh-arrsm-opt
#!/usr/local/bin/zsh-clean
zmodload zsh/zprof
test_fun() {
local -a arr
arr=( "a" )
repeat 20; do
arr+=( $arr )
done
}
test_fun
test_fun
test_fun
zprof
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Mild setarrvalue() optimization
2016-11-08 10:27 [PATCH] Mild setarrvalue() optimization Sebastian Gniazdowski
@ 2016-11-08 15:46 ` Daniel Shahaf
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Shahaf @ 2016-11-08 15:46 UTC (permalink / raw)
To: Sebastian Gniazdowski; +Cc: zsh-workers
Sebastian Gniazdowski wrote on Tue, Nov 08, 2016 at 02:27:04 -0800:
> there's freearray() at end of setarrvalue(). It can be replaced with
> free() if ownership of all strings will be given away:
I see this has been applied.
s/calloc/malloc/ should save a few more milliseconds.
Also reduce code duplication.
Cheers,
Daniel
diff --git a/Src/params.c b/Src/params.c
index 19a8c29..9f449c5 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2651,8 +2651,8 @@ setarrvalue(Value v, char **val)
if (v->end <= pre_assignment_length)
post_assignment_length += pre_assignment_length - v->end + 1;
- p = new = (char **) zshcalloc(sizeof(char *)
- * (post_assignment_length + 1));
+ p = new = (char **) zalloc(sizeof(char *)
+ * (post_assignment_length + 1));
for (i = 0; i < v->start; i++)
*p++ = i < pre_assignment_length ? ztrdup(*q++) : ztrdup("");
diff --git a/Src/mem.c b/Src/mem.c
index 8c7eb80..0ac4009 100644
--- a/Src/mem.c
+++ b/Src/mem.c
@@ -976,18 +976,8 @@ zalloc(size_t size)
mod_export void *
zshcalloc(size_t size)
{
- void *ptr;
-
- if (!size)
- size = 1;
- queue_signals();
- if (!(ptr = (void *) malloc(size))) {
- zerr("fatal error: out of memory");
- exit(1);
- }
- unqueue_signals();
+ void *ptr = zalloc(size);
memset(ptr, 0, size);
-
return ptr;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
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