How to get zval map to identify cpu hog?

Hi, it's the second time I'm running into this: In a rather big project I'm using gearman to enable semi-parallel processing of many small jobs. I'm using PHP 5.6.22-0+deb8u1 with OPcache 7.0.6-dev on Debian. All was well before the code needed refactoring for a new feature: 30 workers processed 4000 jobs/second at around 5% CPU usage. After refactoring (no functional changes), some times after starting the workers, processing is getting slower and slower. After about 2 hours I hit 100% CPU usage, at about 300 jobs/second. Memory usage only doubles from start to stall, which is what I observed before when everything was fine. I suspect this to be a problem of the cycle collector, or with garbage collecting in general. So at any given time, I want PHP to dump all the zval's around, which I have to evaluate manually to find "problematic" ones. This could be triggered by either a function call, or by adding/extending PHP's signal handler and sending that signal to the interpreter process. Where do I have to look at in the sources? Or is there already a tool which does what I want, but didn't find yet? I also learned this _could_ be hash collisions related to reordering and renaming the data in my code, but as I'm currently stuck with 5.6 I can't use the HashDoS related patches floating around here. Any hints on where to find the culprit? Thanks, Thomas