lkml.org 
[lkml]   [1998]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: linux-kernel-digest V1 #2824 (was: elevator)
>On Fri, 13 Nov 1998, Jeffrey B. Siegal wrote:
>
>> I vaguely recall reading in some operating system book that
>> this is modified version of the elevator algorithm
>> meant increase fairness. Otherwise, the access to block 5
>> might be delayed a *long* time if lots of high-value
>> blocks are requested.
>
>But it will never be starved. I do not have hard figures, but I'd
>make an educated guess that the modification Philip proposed will
>be beneficial more often than not.

That depends on how you define benefit. It will decreae the mean
service time, but increase the service time variance. Is that
beneficial? It depends.

Also, adding accesses to the current pass will bias accesses such those
at the end of the disk will be serviced faster than those at the
beginning. This is similar to the one-way vs. two-way elevator issue
discussed by others.





-
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 13:45    [W:0.037 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site