My Apache PHP servers sometimes appear to become CPU bound for around 10 minutes and then go back to being normal. I've looked at these hosts in perf (system profiler) and it's all in PHP (5.6.11).
We need to be able to profile the actual PHP code when this happens to see what is going on. Optimally we would be able to have a profiler installed at all times, and enable it when we catch a box in this condition.
What is a good strategy for examining a CPU saturated PHP web server in production to understand what's going on?