Messages in this thread | | | Date | Sat, 12 Jul 2003 21:23:52 +0100 | From | Dave Jones <> | Subject | Re: 2.5 'what to expect' |
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On Sat, Jul 12, 2003 at 04:10:26PM +0300, Meelis Roos wrote: > elvtune is mentioned here... > > DJ> - Several different IO elevators are available to match different types > DJ> of workload. You can select which one to use with elvtune. > but deprecated here: > > DJ> Deprecated. > DJ> ~~~~~~~~~~~ > DJ> - usbdevfs will be going away in 2.7. The same filesystem can > DJ> be mounted as 'usbfs' in recent 2.4 kernels, and in 2.5.52 > DJ> and above, which is what the filesystem will furthermore be > DJ> known as. > DJ> - elvtune is deprecated (as are the ioctl's it used). > DJ> Instead, the io scheduler tunables are exported in sysfs (see below) > DJ> in the /sys/block/<device>/iosched directory. > DJ> Jens wrote a document explaining the tunables of the new scheduler at > DJ> http://www.lib.uaa.alaska.edu/linux-kernel/archive/2002-Week-44/att-deadline-iosched.txt
Something seems amiss. The deprecated elvtune interface is the old -r/-w/-b command line. I was lead to believe a new elvtune appeared which supports an option for changing the elevator under 2.5, however a quick google doesn't turn up any such patched elvtune, so I'm somewhat puzzled.
> Maybe just suggest the sysfs interface at once and not mention elvtune?
Changing the elevator type per device via sysfs does seem to make sense, however /sys/block/<devicename>/queue/iosched/ doesn't yield anything that would suggest this is possible (yet). I think Jens has patches for this?
Right now, afaics, the only way to change elevator is on a global (all device) basis, booting with elevator=deadline or the like, so it looks like the quote from post-halloween-2.5.txt has jumped the gun a little and is discussing an as-yet unmerged feature. Jens ?
Dave
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