Messages in this thread | | | Date | Sat, 20 Mar 1999 12:07:38 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: disk head scheduling |
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On Sat, 20 Mar 1999, Gerard Roudier wrote: > > The current request queue in Linux is probably a excellent helper for IDE > disks and SCSI disks when using a small number of tagged commands and a > small number of disks at the same time, but for high-end SCSI we want to > use numerous disks at the same time and to queue them a large number of > tagged commands.
This is mainly a problem with the SCSI subsystem, rather than anything else. The SCSI subsystem is not very good at feeding the requests to different disks, much less different controllers.
The basic IO-request queue is fairly simple, and it's certainly not perfect, but most of the problems are actually at a different layer. One obvious one is the SCSI subsystem that forces everything to be on one queue.
Linus
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