Date: Wed, 6 Mar 1996 19:29:02 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: terry@lambert.org (Terry Lambert) Cc: msmith@atrad.adelaide.edu.au, gpalmer@FreeBSD.ORG, jeff@tad.cetlink.net, questions@FreeBSD.ORG Subject: Re: TCP Tuning? Message-ID: <199603061829.TAA08790@labinfo.iet.unipi.it> In-Reply-To: <199603061751.KAA11337@phaeton.artisoft.com> from "Terry Lambert" at Mar 6, 96 10:51:38 am
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> > > > Get a better ethernet card... the ne2k's have a poor performance in
> > > > general because they don't have any on-card RAM to store packets. Get
> > > > either a SMC card or one of the DEC DC21040 based cards.
> >
> > Just for the records... There are PCI-based ne2000 clones, which
> > sell for approx US$60 here. Programmed I/O on the PCI bus should not be
> > slow at all.
>
> Unless you compare it to DMA I/O on the same bus... 8-).
Unless you compare prices...
As I just said in reply to Garret's message, it might be a 5-10% CPU
overhead, which is perfectly tolerable for a board which costs
perhaps half as much. Not to mention the fact that in some countries
some pieces of hardware are simply not available.
On this list there are often strong statements against certain pieces
of hardware just because they don't have top performance, totally
ignoring the price factor and some technical issues.
IMHO, this is a bad thing, because people believes them blindly,
often ending up buying SCSI disks (because "IDE sucks"), with cheap
ISA-based SCSI controllers, or, worse, ISA SCSI controller with an
on-board 4MB used as a cache (so that often they end up doing
programmed I/O to read from the controller's cache!)
----
About IDE drives: I agree that they might not be the best approach
to fast file I/O, but this is what I get on a P133/32MB ram with
a WDC AC21000H 1GB IDE disk:
diani: {21} iozone 128 8192
Writing the 128 Megabyte file, 'iozone.tmp'...32.101562 seconds
Reading the file...30.429688 seconds
IOZONE performance measurements:
4181034 bytes/second for writing the file
4410749 bytes/second for reading the file
Sure, probably the system is more loaded than a SCSI thing:
Cpu states: 0.4% user, 0.0% nice, 33.9% system, 38.5% interrupt, 27.2% idle
Memory: 13M Act 1748K Inact 2032K Wired 80K Free
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND
589 root -6 0 240K 548K sleep 0:02 53.23% 11.79% iozone
but the savings on the SCSI stuff almost get me 16MB RAM. For a
personal workstation, and if I am on a budget, this is the way I would
go.
Luigi
====================================================================
Luigi Rizzo Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it Universita' di Pisa
tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 http://www.iet.unipi.it/~luigi/
====================================================================
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