Everyone knows (or not) that I am a big fan of ARM microcontrollers, as I already have a collection of them…of course, all running Linux.
But I wanted to know about the behavior of multi-core ARMs. As my PandaBoard did not arrive, I asked help from Raul Porcel, Gentoo developer (http://armin762.wordpress.com/) who kindly run some tests on his PandaBoard (Dual Core ARM Cortex A9) and his Nvidia Tegra 2 development kit from Nvidia (Dual Core also).
Well, the results are in the graph. They are compared to 2 different dual-core ARMs, and it is great to see that the speedup on ARM platform was roughly the same as in the PC platform. Note that by speedup I mean performance increase with more processors, and not execution time.
Also, I was curios about Hyper Threading. So, here it is another graph, now comparing x86 machines with multi-core architecture. Thanks here to my friend Alberto Daniel Junior (Sapo) who did a test on a Dell machine with 8 real cores (HT), which shows in Linux as 16 processors.
It is interesting to see that although Linux lists cores with HT as 2 cores, they do not behave as a real processor. Well, the numbers don’t lie…just take a look at the graph