AMD Llano Compiler Performance

Last week were a set of AMD Fusion A8-3850 Linux benchmarks on Phoronix, but for you this week is a look at the AMD Fusion "Llano" APU performance when trying out a few different compilers. In particular, the latest GCC release and then using the highly promising Clang compiler on LLVM, the Low-Level Virtual Machine.

We have looked quite thoroughly at LLVM and Clang as these open-source projects have matured in recent years. We have compared GCC, LLVM/Clang, and DragonEgg (the LLVM optimizer plug-in for GCC 4.5+) and most recently looked at the performance relative to the open-source EKOPath 4 compiler. In this article we're just looking to deliver some fresh numbers of the latest GCC and LLVM/Clang releases from an AMD Fusion system.

The test system had the AMD A8-3850 APU with Radeon HD 6550D graphics, the Gigabyte GA-A75M-UD2H motherboard, 2GB of DDR3 memory, and a 60GB OCZ Vertex 2 SSD. On the software side was Ubuntu 11.04 64-bit with the Linux 3.1 development kernel as of 12 August, GNOME 2.32.1, X.Org Server 1.10.1, and an EXT4 file-system. Testing was only done with the A8-3850 system as that's the only Llano APU we have access to at the moment, but a larger Intel and AMD compiler performance comparison is planned for the next couple of months, pending hardware availability.

Using the GCC 4.5.3 compiler in Ubuntu 11.04, GCC 4.5.3, GCC 4.6.1, and LLVM 2.9 with Clang 2.9 were built from source with their stock compiler flags. The original aim was to also include the Open64 compiler, considering AMD's investments made to this open-source compiler, but the Open64 4.2.4 release failed to properly build on the Llano system. However, GCC and LLVM/Clang are the two dominant compilers right now in the open-source and Linux worlds. As usual, each test case was using its stock compiler flags during the build process for each of the tested compilers. All benchmarking was done in a fully automated manner via the Phoronix Test Suite and accompanying software.