#32727 [Com]: Slow serialize on FreeBSD

ID: 32727 Comment by: runner at protom dot org Reported By: cws at miraclenet dot co dot th Status: Open Bug Type: Performance problem Operating System: FreeBSD PHP Version: 4.*, 5.* New Comment: Very Good! Previous Comments: ------------------------------------------------------------------------ [2005-04-19 02:48:30] cws at miraclenet dot co dot th I forget to mension that the previous result is from my patched version. The result of unpatch one is cws@t42# ./php test_serialize.php version:4.3.11 Length: 2798041 Serialize time: elapse(2.554760) ------------------------------------------------------------------------ [2005-04-19 02:36:12] cws at miraclenet dot co dot th No it don't help me to speed up my test code. This is the result cws@t42$ ./php test.php Content-type: text/html X-Powered-By: PHP/5.1.0-dev <PRE>version:5.1.0-dev Length: 2798041 Serialize time: elapse(2.136879) cws@t42$ /usr/local/bin/php test.php <PRE>version:4.3.11 Length: 2798041 Serialize time: elapse(0.200818) The test code and data can be download at http://freebie.miraclenet.co.th/tmp/test_serialize.tgz The test data may seem too extreme (an array of 2.8M) but it is the one that our customer really use. ------------------------------------------------------------------------ [2005-04-16 16:38:42] sniper@php.net Please try using this CVS snapshot: http://snaps.php.net/php5-latest.tar.gz For Windows: http://snaps.php.net/win32/php5-win32-latest.zip PHP 5.1-dev has got some optimizing done in this part, see if it's any better (without your patch of course) ------------------------------------------------------------------------ [2005-04-16 13:39:18] cws at miraclenet dot co dot th This is a patch t42# diff -u ext/standard/php_smart_str.h /home/cws/php_smart_str.h --- ext/standard/php_smart_str.h Wed Apr 16 16:12:37 2003 +++ /home/cws/php_smart_str.h Sat Apr 16 18:27:30 2005 @@ -32,6 +32,10 @@ #define SMART_STR_PREALLOC 128 #endif +#ifndef SMART_PTR_MAX_PREALLOC +#define SMART_PTR_MAX_PREALLOC 1048576 +#endif + #ifdef SMART_STR_USE_REALLOC #define SMART_STR_REALLOC(a,b,c) realloc((a),(b)) #else @@ -42,8 +46,11 @@ if (!d->c) d->len = d->a = 0; \ newlen = d->len + n; \ if (newlen >= d->a) {\ - d->c = SMART_STR_REALLOC(d->c, newlen + SMART_STR_PREALLOC + 1, what); \ - d->a = newlen + SMART_STR_PREALLOC; \ + size_t pre_alloc = newlen *2;\ + if ( pre_alloc > SMART_PTR_MAX_PREALLOC ) { pre_alloc = SMART_PTR_MAX_PREALLOC; }\ + if ( pre_alloc < SMART_STR_PREALLOC) { pre_alloc = SMART_STR_PREALLOC; }\ + d->c = SMART_STR_REALLOC(d->c, newlen + pre_alloc + 1, what); \ + d->a = newlen + pre_alloc; \ }\ } ------------------------------------------------------------------------ [2005-04-16 13:08:32] cws at miraclenet dot co dot th Description: ------------ serialize use a lot of realloc which are very slow on FreeBSD From - http://rgarciasuarez.free.fr/p5p/p5p-200307-1.pod - Dan Kogai explained that FreeBSD comes with an implementation of malloc() that is optimized for paged memory, and safe from duplicate free() calls. But the downside is that realloc() is very slow. That's usually not a big deal, because most programs don't use realloc() very often -- but perl does. (The default configuration of perl on FreeBSD is to use perl's internal malloc, that hasn't this realloc limitation.) Serialize use a fix incremental value (SMART_STR_PREALLOC in php_smart_ptr.h). It better for serialize to use exponential incremential value to reduce number of realloc. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=32727&edit=1