The OS X Achilles Heel

Why are Apple servers so slow? It's not the hardware.

Johan De Gelas and his team have published the results of their continued study of OS X and why it is so slow in critical applications. The results are not encouraging to corporations considering running the Apple operating system in a server capacity. But the De Gelas team also found it's not Apple hardware at fault: on the contrary, it can often produce better results than Wintel hardware.

De Gelas sees the Achilles heel in the threading system of OS X which he also concludes, contrary to Apple's claims, has not improved significantly with Tiger. Although the limit of two locked threads in the kernel prior to Tiger has been loosened up a bit, De Gelas and his team could see no substantial improvements.

Better with YDL and IBM?

'It is clear that if you plan to run MySQL on Apple hardware, it is better to install YDL Linux than to use OS X. If you need excellent read performance, the maximum performance of your server will be up to 8 times better. If your server is only going to serve a limited number of users, YDL Linux will allow you to run with a less expensive system.'

As to Apple's switch to Intel, De Gelas writes:

'Now that the open source community finally has a decent compiler for the Apple platform, Apple management decide to step over to another architecture. Ironically, right now the Intel architecture needs a super-optimized compiler (Intel's own) to reach the FP performance that the G5 now reaches with a very popular but far less aggressive compiler (gcc).'

But the actual hardware is fine.

'Combined with the data from our first article, we can safely say that the G5 2.7 GHz FP performance is at least as good as the best x86 CPUs. Integer performance seems to be between 70% and 80% of the fastest x86 CPUs, while FP/SIMD performance can actually surpass x86 in certain situations.'

Back to the switch to Intel:

'With the dual-core Power 970MP available and IBM's current outstanding track record when it comes to multi-core CPUs, big question marks can be placed on whether or not the switch to Intel will be such a big step forward as Steve Jobs claims.'

De Gelas and his team could also easily identify corporations migrating to OS X and having to increase their number of servers to keep up with their old workload.

See also
No More Apple Mysteries, Part Two