kenneth johansson wrote: > On Mon, 2007-01-15 at 18:13 +0900, Tejun Heo wrote: >> kenneth johansson wrote: >>> I changed my bios setting for SATA from IDE to AHCI. >>> >>> This resulted in some "interesting" read throughput. >>> >>> plots can be found at http://kenjo.org/~ken/sata/ >>> The plots was done on a live disk so some noise is expected but in the >>> ahci mode the throughput get stuck at 17 MB way to much. >> It's probably not an ahci problem but more of NCQ implementation problem >> in the drive firmware. Please report the result of 'hdparm -I /dev/sdX' >> and try adjust queue depth and see what happens. >> >> http://linux-ata.org/faq.html >> > > It was, when I turn of NCQ with "echo 1 >> /sys/block/sda/device/queue_depth" I get the same performance as when > the BIOS is set to IDE. Can you play with queue depth a bit? e.g. Benchmark queue depth of 4, 8 and 16. > I though that NCQ was intended to increase performance ?? Supposedly. > also the disk is a Westen Digital raptor and it's probably the most > benchmarked drive one could get so I was not expecting a problem with > the drive. Most benchmarked doesn't make the firmware any better, it seems. The raptor Alan talked about, reportedly, locks up after hours of NCQ load too. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
