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Date:      Thu, 02 Sep 2010 14:55:20 +0200
From:      =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To:        Alexander Best <arundel@freebsd.org>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: expand_number() for fetch'es -B and -S switches
Message-ID:  <86pqwwjoef.fsf@ds4.des.no>
In-Reply-To: <20100902122348.GA38047@freebsd.org> (Alexander Best's message of "Thu, 2 Sep 2010 12:23:48 %2B0000")
References:  <20100831180103.GA92584@freebsd.org> <86fwxt5ng1.fsf@ds4.des.no> <20100901222834.GA66517@freebsd.org> <864oe8mpga.fsf@ds4.des.no> <20100902114655.GA9071@freebsd.org> <8639tsl5q0.fsf@ds4.des.no> <20100902122348.GA38047@freebsd.org>

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Alexander Best <arundel@freebsd.org> writes:
> the current maximum buffer limit of fetch(1) actually is around 1G. i
> think 1M is not enough, because if people are pulling data over fast
> lines they'll have almost constant disk writes. how about 100M then?
> ;)

Large buffer sizes are *not* better, since fetch(1) will alternate
between filling the buffer and writing it to disk.  The buffer should
not be too small, but it should not be too large either; the sweet spot
is somewhere around 128 kB.

> on the other hand why have a maximum limit? if people want to have a
> buffer of 100 gigabyte why shouldn't they? it's their decision
> actually.

Good point...  although if they set it too high, either malloc(3) will
fail - if they're lucky - or fetch(1) will crash when the system runs
out of physical RAM and swap, and they'll have to start over.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no



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