Sebastian Bergmann

Last month I got a bit bored and built PHP 4.4.4, PHP 5.0.5, PHP 5.1.6, and current PHP_5_2 (the last two each with CALL, GOTO, and SWITCH VMs) with GCC 3.4.6 and GCC 4.1.1 with -O{0|1|2|3|s}. Yes, this means I built 80 PHP binaries. No, I did not do this manually.

Below are the results of running bench.php with each of the binaries that I built.



As you can see, PHP 5.1 and PHP 5.2 are both around three times faster than PHP 4.4 and PHP 5.0 (GCC 3.4.6, -O2).



Each binary ran the benchmark script five times, the numbers shown are the respective mean from the five runs.

The numbers for PHP 5.1.6 and PHP 5.2 are based upon the CALL-based virtual machine as GOTO and SWITCH did not work for most of the optimization levels.

Update: Yesterday I built PHP 4.4.4, PHP 5.0.5, PHP 5.1.6, and PHP 5.2.0 with ICC 9.1.042 using -O{0|1|2|3|s} and -fast.

Below is a chart that directly compares GCC 3.4.6, GCC 4.1.1, and ICC 9.1.042.



The GCC versions used were Gentoo sys-devel/gcc-4.1.1-r1 and Gentoo sys-devel/gcc-3.4.6-r2 together with Gentoo sys-devel/binutils-2.17.

The CFLAGS used for GCC were "-march=pentium-m -msse3 -O{0|1|2|3|s} -pipe".

The configure options used were "--disable-all --disable-cgi".

The extended body of this posting contains the raw test results as well as detailed information on the hardware used to run the benchmarks.

I updated my previous benchmark of PHP 5.1. This time around I built PHP with GCC 3.4.5, GCC 4.0.2, and GCC 4.1.0.

The bottom line result seems to be that GCC 4 generates slightly slower code:

GCC 3.4.5: 15.223
GCC 4.0.2: 17.896
GCC 4.1.0: 17.847

When I have more time, I will investigate this further using alternative optimizations, including profiling-guided ones.

Over the last couple of days I benchmarked the three execution models (CALL, GOTO, SWITCH) that the new virtual machine of PHP 5.1 offers against PHP 5.0.4 and PHP 4.3.11 (results with GCC 3.4.4, GCC 4.0.1).

Initial results show that PHP 5.1's GOTO-based executor gives a 400% better performance than PHP 4 and PHP 5.0. The benchmark script used is available here.

In PHP 5.1.0 the default executor will be CALL as it is the most tested one. You can use GOTO or SWITCH by using the --with-zend-vm={CALL|GOTO|SWITCH} configure parameter. GOTO and SWITCH currently segfault on the Ackermann benchmark, but this is being worked on.