*BSD News Article 21828


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Newsgroups: comp.os.386bsd.questions
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From: pitts@bigbang.astro.indiana.edu (Jim Pitts)
Subject: Re: ed0: device timeout, freebsd cslip 
Message-ID: <CEDnEn.D9r@usenet.ucs.indiana.edu>
Sender: news@usenet.ucs.indiana.edu (USENET News System)
Nntp-Posting-Host: bigbang.astro.indiana.edu
Organization: Indiana University Astrophysics, Bloomington, IN
References: <1993Oct3.020559.16808@zen.void.oz.au> <CECt8C.29o@Colorado.EDU> <JKH.93Oct4083135@whisker.lotus.ie>
Date: Mon, 4 Oct 1993 14:39:58 GMT
Lines: 43

In article <JKH.93Oct4083135@whisker.lotus.ie> jkh@whisker.lotus.ie (Jordan K. Hubbard) writes:
>	   OB QUESTION:  is anyone else getting simply glacial CSLIP 
>	   performance from FreeBSD epsilon?  With 386BSD 0.1 I had about 
>	   1.1k/sec ftp, with NetBSD 0.9 the lowest I've seen is 1.3k/ sec.  
>	   FreeBSD provides a consistent and stunning .6k/sec.  Even Linux 
>	   pl13 gives .8k/sec!
>
>I get a consistent 1.4 K/sec with my 14.4K FAX modem.  Two factors can
>hose your slip performance, though it sounds like at least the former
>is not your problem but I include it here for completeness:
>
>1.  Serial cards with 16450 non-FIFO'ing UARTS.  My modem uses the 16550A
>    chip with FIFO and it makes a major difference.
>
>2.  Using the com, rather than the considerably faster sio driver.
>
>	   I know I'm using the computing equivalent of a 1 inch penis,
>	   but .6k/sec CSLIP with recognized 16550A UARTs, ~5 MIPS and 
>	   a perfectly clean phone line?  I think I could get better 
>	   throughput by using tree sloths as the transport layer.
>
Boy, you are not far off on that one.  Is there a good reason you are not
using the sio driver?  I get 1.4-1.9K/sec from my 14.4 (USR Sportster) using
ftp/16550A/sio drivers.

The compression features of 14.4K modems can actually HURT your transfer
rate on gzipped files that are ALREADY compressed.  Remember that your
modem has to spend time compressing files before it sends them (that
is how it gets to the speeds it does at some level).  If there is
little redundancy in the data you are transmitting, this can slow you
down a good bit.  I would suggest if you want to compare to other peoples
numbers you provide the transfer rates for:

	1.  gzip'ped files (packed binaries).
	2.  ASCII text files.
	3.  Executable binaries (non packed binaries).

Do this for files above 500K in size to get good statistics.  Finally, after
you do this with ftp, do the same tests with zmodem.  You should get
1.4K/s for binaries, 1.2K/s for packed binaries, and almost 2K/s for ASCII
files.

					Jim