Dne, 12. 12. 2009 07:14:28 je Stan Hoeppner napisal(a): > > I guess my first question is, why is the performance going through > the > Linux system cache buffers ~40% lower than doing a --direct read? > Going > through the Linux buffers is normal system operation. Second > question > is how do I improve buffered performance? Third, why is the sata_sil > driver defaulting to UDMA/100 instead of UDMA/133, even after > identifying the capability of the drive as UDMA/133?
I would think UDMA/100 is the upper limit of your SATA controller, so your actual drive gets limited to UDMA5, although it's capable of UDMA6: > UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5 udma6 > Does this > matter? Yes, it does matter. And is probably at least *one* of the answers to your first two questions. > Is this slowing things down? Last question is, is the > kernel/controller/drive already running at optimal performance, and > I'm > misreading reality? It's most definitely slowing things down. Of course, I may be misreading reality, as you aptly put it ;) -- Regards, Klistvud Certifiable Loonix User #481801 http://bufferoverflow.tiddlyspot.com -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
