From: Bart V. A. <bar...@gm...> - 2009-07-26 07:47:09
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On Sat, Jul 25, 2009 at 7:12 PM, Bart Van Assche <bar...@gm...> wrote: > Results: > * For brd, XFS I/O is typically slower than block device I/O, as > expected. But XFS I/O can be up to 7% faster than block device I/O, > which is not expected. This effect is the strongest for the block size > (4 MB) that is the closest to the CPU cache size (6 MB). The above result has been obtained on a system with a dual core CPU. I have repeated this test with the kernel boot parameter maxcpus=1 added. As you can see with maxcpus=1 XFS I/O is systematically slower than block device I/O on a ram disk (brd.ko). So apparently XFS is able to use multiple CPU cores more effectively than direct device block I/O. Bart. |