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SubjectRe: More on 2.2.18pre2aa2
On Tue, 12 Sep 2000, Rik van Riel wrote:

>We can already set different figures for different drives.

Right.

>Would it really be more than 30 minutes of work to put in
>a different request # limit for each drive that automatically
>satisfies the latency specified by the user?

Note that if you know the transfer rate of each of your harddisk you can
just almost emulate the "in function of time" behaviour by converting from
"throughput" and "latency in function of time", to "latency in function of
bh sized requests". (one userspace script could do that automatically for
example using hdparm to first benchmark the throughput)

The reason I prefer working with "latency in function of bh sized
requests" in kernel space is that I can just use one constant for most of
the blockdevices. Using the same latency setting with the "in function of
time approch" would be wrong instead (and you should gather some hardware
info from the device before you are able to decide a good constant).

Andrea

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