Hi Matt, In case of small size (size <= 128B), your code fit into special case, those handled by allocator's cache. The memory_usage information isn't updated in this case.
128B < size < 256KB - uses zend memeory manager and updates memory_usage information. Seems it works with the same speed. size >= 256KB - utilizes system storage manager (malloc/mmap/...) and checks memory limit. Dmitry. > -----Original Message----- > From: Matt W [mailto:[EMAIL PROTECTED] > Sent: Friday, July 28, 2006 1:43 PM > To: internals@lists.php.net; Dmitry Stogov; Andi Gutmans > Subject: Re: [PHP-DEV] memory_get_usage with new Memory Manager > > > Hi all, > > For my own curiosity regarding the overhead with memory-limit > or keeping track of usage so memory_get_[peak_]usage() can > always be enabled, I just did some quick testing. Using this code > > PHP_FUNCTION(emalloc_tester) > { > int i; > long mem_size; > void *ptr; > > if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", > &mem_size) == > FAILURE) { > return; > } > > for (i = 0; i < 100000; i++) { > ptr = emalloc(mem_size); > efree(ptr); > } > } > > with different mem_size's and timing it. Using the latest > CVS files for 5.2; only difference is the > --enable-memory-limit option. Dual 930MHz PIII Windows 2000 > system (yes, *both* CPUs were maxed after mem_size got larger > than would fit into a block :-)). > > -ms- > Size On Off > ------------------ > 8 10.6 10.8 > 32 10.7 10.8 > 128 10.6 10.8 > 512 16.2 16.5 > 1k 16.3 16.5 > 8k 16.3 16.6 > 64k 16.3 16.6 > 128k 16.3 16.6 > 256k 2155 2140 > 512k 2225 2210 > > Interesting that it was consistently faster for me *with* > memory-limit at the smaller sizes, which I assume are by far > the most-used. Does this help at all? :-) > > > Matt > > -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
