Date: Thu, 17 Feb 2005 01:55:25 +0000 From: Chris Hodgins <chodgins@cis.strath.ac.uk> To: Julian Elischer <julian@elischer.org> Cc: current@freebsd.org Subject: Re: where did all my memory go? (file system cache) Message-ID: <4213F98D.7020304@cis.strath.ac.uk> In-Reply-To: <4213D3AA.70809@elischer.org> References: <1108584730.95661.12.camel@server.mcneil.com> <20050216201716.GA28436@odin.ac.hmc.edu> <4213B3C8.3090508@centtech.com> <1108588393.12275.9.camel@server.mcneil.com> <20050216214031.GA2787@odin.ac.hmc.edu> <4213D3AA.70809@elischer.org>
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Julian Elischer wrote: > slightly off topic but.. > > Brooks Davis wrote: > >> On Wed, Feb 16, 2005 at 01:13:13PM -0800, Sean McNeil wrote: >> >> >> The concept that most of your memory should be entierly free when the >> system is not under load is simply wrong. The simplistic world view of >> memory being allocated to a specific task or entierly free simply isn't >> correct for all that it makes for nice graphs anyone can pretend they >> understand. You can produce some sort of aproximation of the output you >> see on other systems by modifying the program to include inactive memory >> in free memory. That's what I did with Ganglia. >> > > what I really want is a way to FORce certain pages out of cache. > In particular I need to verify teh correctness of the version on 2ndary > storage.. > > what I want is: > > int fd = open("myfile",...); > write1GBfiletodisk(fd, data); > ioctl(fd, PURGEFROMCACHE); > perform_md5(fd); > > and be sure that teh MD5 is that of what is on the disk. > not what is in RAM. > >> >> -- Brooks >> >> >> > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > IANAE but could you not use the O_DIRECT flag with open? O_DIRECT eliminate or reduce cache effects HTH Chris
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