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Date:      Fri, 16 May 1997 11:27:50 +0300 (EEST)
From:      Narvi <narvi@haldjas.folklore.ee>
To:        Terry Lambert <terry@lambert.org>
Cc:        James Mansion <james@westongold.com>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: mmap()
Message-ID:  <Pine.BSF.3.96.970516110353.6813E-100000@haldjas.folklore.ee>
In-Reply-To: <199705152313.QAA16073@phaeton.artisoft.com>

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On Thu, 15 May 1997, Terry Lambert wrote:

> 
> It would have a cost higher than not doing it (ie: non-zero).  Using
> mmap() and then doing sequential I/O is probably a very limited market,
> so John would have to amke a decision to accept the non-0 degradation
> on that basis.
> 

Well, isn't grep doing the same? Mmap a file and then walk it line by line
and output the line matching the regular expression? Any program that
processes some kind of text file line by line will most probably express
the same kind of access pattern. 

I am not sure, but in case of several processes accessing one file using
MADV_WILLNEED / MADV_DONTNEED could perhaps help?

	Sander

By the way - in the source of grep, madvise(.. MADV_SEQUENCIAL ..) is
commented for being slover. I will give it a try...

[a huge snip]

> 
> 					Regards,
> 					Terry Lambert
> 					terry@lambert.org
> ---
> Any opinions in this posting are my own and not those of my present
> or previous employers.
> 




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