On Mon, 2 Apr 2012 10:55:31 -0700 Jerry Toung <jryto...@gmail.com> wrote:
> I am convinced that there is a bug in the CAM code that leads to I/O > starvation. > I have already discussed this privately with some. I am now bringing this up > to > the general audience to get more feedback. > I've observed this with my onboard ATI IXP700 AHCI SATA controller and 2 or 3 SATA disks. When one disk gets busy all others are pretty much blocked until it finishes. Seems to me that this behavior is (fairly) recent. [snip] > I have a patch and it fixes those problems. I can share it to the list > if requested to. > da0 and da1 now both automatically get 126 openings and based on that, > extra logic implements fairness in cam/cam_xpt.c. No more 0 MB/s on > da1. This is on 8.1-RELEASE FreeBSD. > It would be interesting to see your patch. I always run HEAD but maybe I could use it as a base for my own mods/tests. -- Gary Jennejohn _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"