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Date:      Sun, 12 Nov 1995 01:17:11 -0600 (CST)
From:      Joe Greco <jgreco@brasil.moneng.mei.com>
To:        dyson@freefall.freebsd.org (John Dyson)
Cc:        current@freebsd.org
Subject:   Re: ISP state their FreeBSD concerns
Message-ID:  <199511120717.BAA25951@brasil.moneng.mei.com>
In-Reply-To: <199511120557.VAA24917@freefall.freebsd.org> from "John Dyson" at Nov 11, 95 09:57:36 pm

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Hi,

> > 3.	A concern about things in FreeBSD that impact INN performance, or
> > 	force them to compile INN special for FreeBSD.  They are talking
> > 	about MMAP support.  Although some have stated in the mailing lists
> > 	that not using MMAP on FreeBSD doesn't have a penalty, these guys
> > 	are almost universally convinced that not using MMAP defeats the
> > 	purpose of all the RAM they bought or will yield slower performance
> > 	than some other system, probably because on a lot of other operating
> > 	systems this is very true.
> 
> There have been problems with this.  If anyone is willing to work with
> me "intimately" on this -- including helping me track the problems
> down, let me know.  I think that it should be better now in -current,
> but I need feedback.  I probably know the VM system as well as anyone,
> but I don't have a user site to work directly with.  I am very flexible,
> and generally very easy to work with -- this is a call for participation!!!

I would much rather do whatever I can to help you track down problems now
and gain a much better system ...  and I can certainly give you full access
to news.sol.net, even console access thanks to serial consoles  :-)

>From a kernel debugging standpoint I am rather weak, but am pretty good at
quantifying problems and building tests to cause repeatable failures.

> > 8.	File creation (particularly directories) appears to be slow compared
> > 	to other BSD-like systems.  They say the stats for INN and CNEWS
> > 	for articles processed per second are quite a bit lower than that
> > 	on some "other" systems.  They say that file deletion seems to be
> > 	a bit slower than BSDI, but not by much.  I think they are talking
> > 	2.0.5 on this item, although one ISP was experimenting with 1026 SNAP.
> 
> I am working on this stuff right now.  Give me benchmarks!!!!  I'll
> do what I can.

This noted as well.  I am frustrated that I cannot seem to hit more than a
PEAK of 4 arts/sec without MMAP, or around 5.5-6 with MMAP.  My pet Solaris
news server, with PrestoServe and 128MB RAM, and only 4 disks, can peak out
at around 15.  I do know that with only 48MB of RAM, news.sol.net takes more
of a hit on history lookups (expected), but with the I/O load spread over a
dozen disks, I would expect that would compensate somewhat...

I haven't been able to quantify exactly what the factors are.  news.sol.net
will hopefully get an upgrade to 64MB or 80MB in the coming month, which
will help level the playing field between it and Spool (the Solaris box).

> Firstly, regarding performance issues (incl MMAP probs)  send benchmarks &/or
> example code!!!  Those are the things that get me to work on the problems
> the quickest!!!  (Just saying innd doesnt work with MMAP does not help,
> even though it is better than not knowing there is a problem, I need test code
> that breaks.)  We also need more people to help with certain kernel
> issues (Linux compat probs, for example.)   Also, the 2.1 release has slowed us
> down alot.

Test code that breaks, problematic - at least as far as MMAP goes.  MMAP
appears to work fine at first glance, but the panic rate of the system goes
from once every few weeks to once every two or three days.  I have no idea
what tickles it.

I can probably get you some numbers in terms of file creation/removal rates
on both Solaris x86 and FreeBSD 2.1R (well, SNAP).  I don't know what they
will look like so it would be a doubly interesting test for me to perform.

If there is anything I can do to help your testing and development - for
heaven's sake, LET ME KNOW.  I am quite resourceful and am sure most any
need you might have could be addressed....

Your efforts ARE appreciated and it's the least I can do.

... Joe

-------------------------------------------------------------------------------
Joe Greco - Systems Administrator			      jgreco@ns.sol.net
Solaria Public Access UNIX - Milwaukee, WI			   414/342-4847



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