Messages in this thread |  | | | Subject | Re: [Ext2-devel] Re: Fall back io scheduler for 2.6.15? | | From | Mingming Cao <> | | Date | Mon, 16 Jan 2006 11:38:18 -0800 |
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On Fri, 2006-01-13 at 17:49 -0800, Andrew Morton wrote: > Mingming Cao <cmm@us.ibm.com> wrote: > > > > On 2.6.14, the > > fall back io scheduler (if the chosen io scheduler is not found) is set > > to the default io scheduler (anticipatory, in this case), but since > > 2.6.15-rc1, this semanistic is changed to fall back to noop. > > OK. And I assume that AS wasn't compiled, so that's why it fell back? >
AS was compiled, and AS is set as the default scheduler. But since 2.6.15 doesn't recognize "elevator=as" (we need to say "elevator=anticipatory"), so in 2.6.15, elevator_setup_default() will explicitly fall back to "noop" scheduler.
2.6.14 doesn't recognize "elevator=as" either, but it fall back to the default scheduler instead. Which makes more sense, as Jen pointed out.
> I actually thought that elevator= got removed, now we have > /sys/block/sda/queue/scheduler. But I guess that's not very useful with > CONFIG_SYSFS=n. > > > Is there any reason to fall back to noop instead of as? It seems > > anticipatory is much better than noop for ext3 with large sequential > > write tests (i.e, 1G dd test) ... > > I suspect that was an accident. Jens? > > > ------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. Do you grep through log files > for problems? Stop! Download the new AJAX search engine that makes > searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! > http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click > _______________________________________________ > Ext2-devel mailing list > Ext2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/ext2-devel >
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