Re: [PATCH] sata_sil: Greatly improve DMA support

From: Jeff Garzik
Date: Sat May 19 2007 - 18:04:12 EST


Indan Zupancic wrote:
This patch seems to work with my SiI 3512, though I don't notice any
difference, neither a speedup, nor a slowdown. Hdparm gives the same
speeds (-tT), and cp -a'ing kernel sources is abysmal slow in both cases,
(need to look into that one) so I didn't really test it that well.


It won't result in much of a speedup, except in situations where IOMMU or other situation that causes you to run into the 64k boundary being an issue -- generally only on huge transfers.

A good measure is to dd(1) to/from the block device, rather than using a filesystem. As has been shown on LKML, the filesystem can really slow things down in some cases.

Jeff


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