lkml.org 
[lkml]   [1999]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: disk head scheduling
On Wed, 24 Mar 1999, Gerard Roudier wrote:

> You only thought IDE and it what I pointed out, btw.
> For SCSI with 1 queue per device, if we are globally plugged we lose
> time (think of SMP, and interruptions), and if we discard the plug, we
> may break the coalescencing and sorting, and then just provide devices
> with bunches small IOs.

I admit that not implementing per-queue plugs at that time was a mistake.
The time in which the plug is being held should be very short relative to
actual I/O times, though, just enough to let the higher layers complete
putting all those small requests and colaescencing them, which is a
CPU <--> memory operation.

Cheers,

Gadi


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:51    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site