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SubjectRe: mmap() is slower than read() on SCSI/IDE on 2.0 and 2.1
Hi,

On Mon, 14 Dec 1998 03:26:33 -0800, "David S. Miller"
<davem@dm.cobaltmicro.com> said:

> read() does more prefetching than mmap() faults do, at least this was
> the story last time I was playing around in this area...

For my own disks here, I'm now getting the same throughput via mmap
(using grep) as using read(): about 5MB/sec. <grin>

It will be pretty simple to add a soft-page-fault fencepost to the page
cache to allow us to prime the next readahead chunk before we have
finished accessing the current one in the case of sequential access,
which will allow us to sustain even faster sequential IO rates on fast
disks.

--Stephen

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