Date: Fri, 30 Nov 2001 16:34:05 -0600 From: Alfred Perlstein <bright@mu.org> To: Luigi Rizzo <rizzo@aciri.org>, freebsd-hackers@FreeBSD.ORG Subject: Re: TCP Performance Graphs Message-ID: <20011130163405.O46769@elvis.mu.org> In-Reply-To: <20011130171418.B96592@ussenterprise.ufp.org>; from bicknell@ufp.org on Fri, Nov 30, 2001 at 05:14:18PM -0500 References: <20011130141100.B90969@ussenterprise.ufp.org> <20011130112215.H30981@iguana.aciri.org> <20011130135042.G46769@elvis.mu.org> <20011130135402.H46769@elvis.mu.org> <20011130125839.A88302@ussenterprise.ufp.org> <20011130102928.E30981@iguana.aciri.org> <20011130141100.B90969@ussenterprise.ufp.org> <20011130112215.H30981@iguana.aciri.org> <20011130135042.G46769@elvis.mu.org> <20011130171418.B96592@ussenterprise.ufp.org>
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* Leo Bicknell <bicknell@ufp.org> [011130 16:14] wrote:
>
> First off, apologies to Luigi, I was shooting off my mouth.
Understandable, it's easy to get heated about an issue when
it weighs so much in ones mind. I've done the same on several
quite memorable occasions.
> Second off:
>
> On Fri, Nov 30, 2001 at 01:50:42PM -0600, Alfred Perlstein wrote:
> > I was about to set the default in -stable to Leo's suggested values,
> > it seems that -current already has the delta he wants in it,
> > my question is, was anything else changed along the lines of the
> > number of nmbclusters allocated in -current to go along with
> > this change?
>
> On Fri, Nov 30, 2001 at 01:54:02PM -0600, Alfred Perlstein wrote:
> > It seems not, I've committed the change.
>
> When I proposed this before there was a bit of a debate about
> needing to increase clusters and MBUF's. To summarize, I think
> we took the following away from it:
>
> * For most users it makes no difference, as they are far from the
> limits.
Agreed.
> * This will make a small number of people who aren't hitting
> limits now hit an MBUF limit.
>
> - These people probably need increases anyway, as they are
> too close to the limit now.
>
> - Hitting the MBUF limit is fairly, well, harsh, and we might
> want to add syslog or other logged warnings at like 90%
> utilization or something.
This is a very good idea.
> At a minimum I think:
>
> * There needs to be a note in the errata for the release this
> goes in mentioning more MBUF's might be needed.
>
> * LINT should be updated with a comment and a value 2 to 4 times
> GENERIC's default as the default listed value.
Hmm, well the GENERIC default is some mathematical operation on
maxusers. We really ought to make this scale as a default relative
to the amount of ram in the system, rather than some low hardcoded
value. NetBSD has some stuff for this in their buffercache sizing
algorithm in netbsd-stable. It might be worth checking out, the
formula is quite smart such that it has a decent size when system
ram is low, then for each meg above X it increases it by some
percentage. I find it to be too low, but whatever. :)
>
> * The logging at 90% usage should be investigated. I can probably
> generate patches for that over the weekend, provided I can find
> a good way to rate limit them.
Generating one message is usually a good idea, however you could
invesitagate how the "icmp response limit" messages are buffered.
--
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
http://www.morons.org/rants/gpl-harmful.php3
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