From: Matt Dillon <dillon@earth.backplane.com>
To: Charles Randall <crandall@matchlogic.com>
Cc: Roger Larsson <roger.larsson@norran.net>,
Rik van Riel <riel@conectiva.com.br>,
arch@FreeBSD.ORG, linux-mm@kvack.org, sfkaplan@cs.amherst.edu
Subject: Re: RE: on load control / process swapping
Date: Wed, 16 May 2001 10:14:15 -0700 (PDT) [thread overview]
Message-ID: <200105161714.f4GHEFs72217@earth.backplane.com> (raw)
In-Reply-To: <5FE9B713CCCDD311A03400508B8B30130828EDA8@bdr-xcln.corp.matchlogic.com>
We've talked about implementing O_DIRECT. I think it's a good idea.
In regards to the particular case of scanning a huge multi-gigabyte
file, FreeBSD has a sequential detection heuristic which does a
pretty good job preventing cache blow-aways by depressing the priority
of the data as it is read or written. FreeBSD will still try to cache
a good chunk, but it won't sacrifice all available memory. If you
access the data via the VM system, through mmap, you get even more
control through the madvise() syscall.
-Matt
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next prev parent reply other threads:[~2001-05-16 17:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-16 15:17 Charles Randall
2001-05-16 17:14 ` Matt Dillon [this message]
2001-05-16 17:41 ` Rik van Riel
2001-05-16 17:54 ` Matt Dillon
2001-05-16 19:59 ` Rik van Riel
2001-05-16 20:41 ` Matt Dillon
2001-05-18 5:58 ` Terry Lambert
2001-05-18 6:20 ` Matt Dillon
2001-05-18 10:00 ` Andrew Reilly
2001-05-18 13:49 ` Jonathan Morton
2001-05-19 2:18 ` Rik van Riel
2001-05-19 2:56 ` Jonathan Morton
2001-05-16 17:57 ` Alfred Perlstein
2001-05-16 18:01 ` Matt Dillon
2001-05-16 18:10 ` Alfred Perlstein
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