Re: Is 2.3.7 only better for SMP

David S. Miller (davem@redhat.com)
Mon, 21 Jun 1999 19:30:04 -0700


Date: Mon, 21 Jun 1999 22:14:36 -0400
From: Jim Nance <jlnance@sailboat.mis.uncwil.edu>

Just a quick question about 2.3.7. Are the improvements only
going to help SMP machines, or are they good for uniprocessor
machines too?

It will help on uniprocessors too, certainly.

The advantage on both uniprocessor and SMP is that instead of writes
going through the buffer cache, they go straight through the page
cache. This is noticable especially if the next thing that happens is
a read of the just-written data, because the old code would need to
copy the data out of the buffer cache and into the page cache, whereas
now it would just be in the right place and copied directly to user
space or mapped into the process's vm.

One decent example of this case is a kernel build, generating all the
.depend etc. files and then reading them back almost immediately.

Later,
David S. Miller
davem@redhat.com

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