New Memory Manager

Hi, Recently I took a look into jemalloc and tcmalloc internals and tried to borrow some ideas. You may check the result at https://github.com/dstogov/php-src/tree/xx_malloc. It's a dirty prove of concept implementation of New Memory Manager for PHP. It was tested only on Linux, release, non-ZTS build. It misses support for debug mode and ZTS yet. The main advantage is small but consistent speed improvement on real-life applications. I would appreciate if you bench it vs vanilla PHP-5.6 on your applications, review the code from performance and security points of views, and come with comments, ideas and criticism. (For example: may be someone would suggest how to avoid check for USE_ZEND_ALLOC=0 to allow system malloc() usage on each emalloc() call? How to reduce cost of statistics collection?) Currently, I'm not sure if 5% speed improvements costs the effort. The results of my benchmarks follow. Thanks. Dmitry. *PHP-5.6 32-bit* zend_alloc xx_malloc Improvement blog 105.6 109.7 3.88% drupal 1625.0 1667.6 2.62% fw 231.6 286.4 23.66% hello 12048.4 11865.9 -1.51% qdig 464.4 495.3 6.65% typo3 563.8 584.9 3.74% wordpress 188.9 196.8 4.19% xoops 132.7 140.0 5.50% scrum 181.6 192.7 6.11% ZF1 Hello 1153.2 1228.4 6.52% ZF2 Test 263.0 275.5 4.75% *PHP-5.6 64-bit* zend_alloc xx_malloc Improvement blog 99.0 102.3 3.33% drupal 1531.1 1604.2 4.78% fw 197.6 206.5 4.50% hello 11702.0 11875.2 1.48% qdig 451.1 476.8 5.70% typo3 541.8 568.7 4.96% wordpress 176.5 185.8 5.27% xoops 126.1 134.5 6.66% scrum 169.3 174.9 3.31% ZF1 Hello 1042.9 1119.6 7.35% ZF2 Test 238.4 242.5 1.72%