-------- In message <canczdfowid9zsbje8u+pm5lylsklgqu9m2pvdkufbuccv_q...@mail.gmail.com>, Warner Losh writes:
>I never enabled it because I never had a good car size as the default. I'm >guessing it's somewhere on the order of 2 times the queue size in >hardware, but with modern drives I think phk might be right and that >disabling disksort entirely might be optimal, or close to optimal. I think that is a given for SSDs. For disks I fear it would be a model-by-model determination. The situation is quite different for "traditional" and shingled drives for instance, or if, God forbid, the rumours are true and we'll see IBM3380-style dual head assemblies in the market again. I guess the kernel could turn the disksort on/off a few times and only leave it on if it improves things. But first, Somebody Should™ benchmark to see if disksort *ever* is an improvement on contemporary disks. Poul-Henning PS: If somebody really want to improve disk- and ssd- performance, the low-hanging fruit is to write a log-structured storage engine under UFS, to make life easier for flash-adaptation layers and shingling drives. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
