The proliferation of multicore CPUs and the inability of our learned CPU vendors to squeeze many more GHz into their designs means that often the only way to get additional performance is by writing clever parallel software. One problem we were having is that some of our batch processing jobs were taking too long to run. In order to speed the processing, we tried to split the processing file into half, and let a separate PHP process run each job. Given that we were using a dual core server, each process would be able to run close to full speed (subject to I/O constraints).Here is our technique...