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Date: Wed, 10 Oct 2001 09:55:36 -0600
From: "'adilger@turbolabs.com'" <adilger@turbolabs.com>
To: Venkatesh Ramamurthy <Venkateshr@ami.com>
Cc: "'xuan--lkml@baldauf.org'" <xuan--lkml@baldauf.org>,
        "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: Re: dynamic swap prioritizing
Message-ID: <20011010095536.C10443@turbolinux.com>
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On Oct 10, 2001  11:23 -0400, Venkatesh Ramamurthy wrote:
> > If this is to be generally useful, it would be good to find things
> > like max sequential read speed, max sequential write speed, and max
> > seek time (at least). Estimates for max sequential read speed and
> > seek time could be found at boot time for each disk relatively
> > easily, but write speed may have to be found only at runtime (or
> > it could all be fed in to the kernel from user space from benchmarks
> > run previously).
> 
> Maybe we can find out the statistics for the first time (or when swap is
> created) and store this information in the swap partition itself. This would
> allow us to compute time consuming statistics only once. Also we need to
> create new fields in the swap structure for this purpose.

I'd rather just have the statistic data in a regular file for ALL disks,
and then send it to the kernel via ioctl or write to a special file that
the kernel will read from.  I don't think it is critical to have this
data right at boot time, since it would only be used for optimizing I/O
access and would not be required for a disk to actually work.

Cheers, Andreas
--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

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