On Mon Jul 07, 2008 at 17:00:58 +0200, Neal H. Walfield wrote: >I ran an application benchmark on Viengoos. Specifically, the >application is derived from the GCbench program. You can find it >here:
>Each invocation includes approximately 12 words of payload and each >reply contains 2 words. This suggests an RPC overhead of 1350 cycles >or 1.2 us. > >The 4.2 us represents approximately 5000 cycles. This leaves 3650 >unaccounted cycles. This seems to be a bit more than one can simply >accounted to secondary cache effects, however, perhaps ping pong >really measures the very hot case and I'm running with very cold >caches. I hope someone else can suggest how to figure out to what end >these cycles are being put, has a theory, or can confirm that these >cycle counts are not, in fact, too high. That seem about right to me in terms of cache effects. ping-pong runs very hot. Next step would be to turn on performance monitoring counters and get a count of cache misses etc. Cheers, Benno
