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Date:      Thu, 29 Jul 1999 04:04:04 -0500 (EST)
From:      "John S. Dyson" <dyson@iquest.net>
To:        crandall@matchlogic.com (Charles Randall)
Cc:        hackers@freebsd.org, toasty@dragondata.com (Kevin Day)
Subject:   Re: Replace/rewrite reverse.c for tail(1)
Message-ID:  <199907290904.EAA57212@dyson.iquest.net.>
In-Reply-To: <64003B21ECCAD11185C500805F31EC030378660F@houston.matchlogic.com> from Charles Randall at "Jul 28, 1999 09:27:28 am"

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Charles Randall said:
> 
> Out of 128M of ram, it's swapped nearly everything else out to keep 85M of
> this 400M file in ram, even though it will never touch it again. :)
> 
> I see two possible fixes for this. One could be madvise'ing periodically
> with MADV_DONTNEED. If I understand correctly, this would help a bit, right?
> 
> Or, mmap smaller regions of the file, and keep moving the buffer. This would
> also help with files exceeding mmap's limits.
> 
> 
> Any thoughts?
> 
Unless the ability has been removed recently, setting the physical
memory soft limit can help a very little bit also:

bash> ulimit -m 16384

can make a program a little more friendly to it's neighbors.  The
soft (in both senses) limit is mushy, but provides some hints when
paging ensues.

-- 
John                  | Never try to teach a pig to sing,
dyson@iquest.net      | it makes one look stupid
jdyson@nc.com         | and it irritates the pig.


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