Re: (reiserfs) Re: More on 2.2.18pre2aa2

[Matthew Kirkwood]

On Tue, 12 Sep 2000, Rik van Riel wrote:

[ outrageous cc: list trimmed ]

> > >We simply keep track of how old the oldest request
> > >in the queue is, and when that request is getting
> > >too old (say 1/2 second), we /stop/ all the others
> > 
> > Going in function of time is obviously wrong. A blockdevice can
> > write 1 request every two seconds or 1 request every msecond.
> > You can't assume anything in function of time _unless_ you have
> > per harddisk timing informations into the kernel.
> 
> Uhmmm, isn't the elevator about request /latency/ ?
> 
> And if so, in what unit do you want to measure
> latency if it isn't time?

Number of requests which get serviced between the
insertion and completion of the request.  Maybe
scaled by the average i/o queue length[0].

Matthew.

[0] Insert obligatory "why oh why" on Linus' not
    taking SCT's sar/iostat patches.

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