Re: Choosing a scheduler a boot time

[Stephen Gardner <stephen-rhel uk org>]

On Mon, 21 Mar 2005, Tom Sightler wrote:

> echo "deadline" > /sys/block/hda/queue/scheduler
>
> to select the deadline scheduler for only hda.  It's an excellent option
> for benchmarking, or for systems that have different volumes with
> distinctly different IO characteristics.

Tom,
	Just a quick note on the sysfs per-device scheduler selector. I 
didn't find it on my system and did some digging and I'm not sure that it 
made it into the RHEL4 release.

The code for

static struct queue_sysfs_entry queue_iosched_entry
[...]

went into the mainline kernel around the 2.6.10-rc stage kernel (from what 
I can tell) and I don't think RHEL4 has it.

It's certainly useful to know about though and is present in FC3s 
2.6.10-1.770  kernel.

Regards,
	Stephen

References:
kernel-2.6.9-5.0.3.EL.src.rpm   package
kernel-2.6.10-1.770_FC3.src.rpm package
drivers/block/ll_rw_blk.c       kernel source file
http://linux.bkbits.net:8080/linux-2.6/cset 1 1938 166 22