Re: Aligning file system data
From: Robert Hancock
Date: Tue Mar 29 2005 - 23:53:21 EST
John Richard Moser wrote:
How likely is it that I can actually align stuff to 31.5KiB on the
physical disk, i.e. have each block be a track?
I don't think this is very likely. Even being able to find out what the
physical disk arrangement is, or whether it is consistent in terms of
track size, etc. seems unlikely.
Rather than leveraging the track cache, would it be less expensive for
me to simply read in blocks totaling about 16 or 32KiB all at once?
For block sizes that small I think that the kernel should be smart
enough to do this itself, there is no need to concern with such low
level details in the application.
How much more latency is involved in (B) than in (C)? Does crossing a
track boundary incur anything expensive?
Given that both the disk and the kernel will likely read far more than
32KB ahead I can't see much difference other than the overhead inside
your application..
--
Robert Hancock Saskatoon, SK, Canada
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