From: Sebastian Gniazdowski <psprint2@fastmail.com>
To: zsh-workers@zsh.org
Subject: [PATCH] zrealloc on array+=( )
Date: Sun, 26 Feb 2017 04:06:44 -0800 [thread overview]
Message-ID: <1488110804.4168166.893166432.40AFA0C2@webmail.messagingengine.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 696 bytes --]
Hello,
optimization that finally targets much common use case and can sometimes
lead to faster Zsh startup.
fun() {
local -a arr
repeat 1000; arr+=( "The appended test string of medium length" );
}
local -F SECONDS=0; fun; echo $SECONDS
100 milliseconds vs 4 milliseconds. Just 1000 repetitions. For 5000, it
is 2.2 seconds vs 4 milliseconds.
I aggregate logs during startup, but didn't get gain as I forgot that I
aggregate as strings (~1000 $'\n' entries). Other tests shown that this
is best aggregation available – strings. So I'm in luck. But now there
could be superior and expected array aggregation.
--
Sebastian Gniazdowski
psprint2@fastmail.com
[-- Attachment #2: array_zrealloc.diff --]
[-- Type: text/plain, Size: 2907 bytes --]
diff --git a/Src/params.c b/Src/params.c
index 19cbb1c..2af24b5 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2723,24 +2723,58 @@ setarrvalue(Value v, char **val)
*p++ = *r++;
}
} else {
- p = new = (char **) zalloc(sizeof(char *)
- * (post_assignment_length + 1));
-
- for (i = 0; i < v->start; i++)
- *p++ = i < pre_assignment_length ? ztrdup(*q++) : ztrdup("");
- for (r = val; *r;) {
- /* Give away ownership of the string */
- *p++ = *r++;
- }
- if (v->end < pre_assignment_length)
- for (q = old + v->end; *q;)
- *p++ = ztrdup(*q++);
- *p = NULL;
+ /* arr+=( ... )
+ * arr[${#arr}+x,...] = */
+ if (post_assignment_length > pre_assignment_length &&
+ pre_assignment_length <= v->start &&
+ pre_assignment_length > 0 &&
+ v->pm->gsu.a->setfn == arrsetfn)
+ {
+ p = new = (char **) zrealloc(old, sizeof(char *)
+ * (post_assignment_length + 1));
+
+ p += pre_assignment_length; /* after old elements */
+
+ /* Consider 1 < 0, case for a=( 1 ); a[1,..] =
+ * 1 < 1, case for a=( 1 ); a[2,..] = */
+ if (pre_assignment_length < v->start) {
+ /* Above <= implies we should run for i < v->start */
+ for (i = pre_assignment_length; i < v->start; i++) {
+ *p++ = ztrdup("");
+ }
+ }
+
+ for (r = val; *r;) {
+ /* Give away ownership of the string */
+ *p++ = *r++;
+ }
+
+ /* v->end doesn't matter:
+ * a=( 1 2 ); a[4,100]=( a b ); echo "${(q@)a}"
+ * 1 2 '' a b */
+ *p = NULL;
+
+ v->pm->u.arr = NULL;
+ v->pm->gsu.a->setfn(v->pm, new);
+ } else {
+ 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("");
+ for (r = val; *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);
+ }
DPUTS2(p - new != post_assignment_length, "setarrvalue: wrong allocation: %d 1= %lu",
post_assignment_length, (unsigned long)(p - new));
-
- v->pm->gsu.a->setfn(v->pm, new);
}
/* Ownership of all strings has been
next reply other threads:[~2017-02-26 12:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-26 12:06 Sebastian Gniazdowski [this message]
2017-03-04 13:47 Sebastian Gniazdowski
2017-03-04 17:22 ` Bart Schaefer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1488110804.4168166.893166432.40AFA0C2@webmail.messagingengine.com \
--to=psprint2@fastmail.com \
--cc=zsh-workers@zsh.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/zsh/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).