[updated, quad core results] BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 7, 2009 12:28 UTC (Mon) by mingo (subscriber, #31122)
In reply to: BFS vs. mainline scheduler benchmarks and measurements by nix
Parent article: BFS vs. mainline scheduler benchmarks and measurements

Today i've measured and posted single-socket non-NUMA quad-core results as well:

"[quad core results] BFS vs. mainline scheduler benchmarks and measurements "

As the graphs show it, the quad results are similar to the 8-core results. So it wasnt NUMA or 16 cpus that made the difference.

Btw., you'd be wrong to treat an 8 core box with HyperThreading as a 16 core box. The physical resources are in essence that of an 8 core one - it's just more spreadable.

BFS should have no design disadvantage from HyperThreading, as siblings share the cache.

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[updated, quad core results] BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 7, 2009 14:13 UTC (Mon) by nix (subscriber, #2304) [Link]

Interesting.

(With regard to hyperthreading you are of course right that the physical resources are those of the physical cores, but surely unless you are HT-aware you will get lower performance on an HT system than otherwise, because you won't know to e.g. schedule threads of the same process on the same physical core if possible, to maximize cache sharing. But I know you know all this as the current mainline scheduler does it :) )