Serial overruns/collisions (incoming only oddities)

Serial overruns/collisions (incoming only oddities)

Post by Robert Loga » Sat, 06 Feb 1999 04:00:00



Ive been using Win98 in my Dell XPS R450 for ages now,
due to my inability to get linux to work with dial-up
connections properly (win98 is fine). As a long long
time
linux user (pl15f 0.99 was my startpoint), I have found
this galling, and thus decided to investigate heavily.

I have a 100k ASCII text file ive been using since my
1st 14.4k modem which has highlighted various speed
improvements of my connection over time. When I got
my new Dell and 56k modem (connecting to a 33k ISP),
I thought i would get a reasonable throughput. The
oddness begins.

From PC to ISP
100k gzipped file (v fast)
100k text file (v fast)

From ISP to PC
100k gzipped file (v fast)
100k text file (hangs - or very very slow - 0.15k/s)

Thus, any web browsing, telnetting, or whatever is
abysmally slow - text stuff just gets stuck. But
any uploads, or compressed data is fine!

The PC's connection is via CSLIP (PPP suffers the
same), with the port set at 115200, the IRQ is
not in conflict, indeed, I have been using the
same DIP script/cfgs (accounting for upgrades)
since my 1st kernel.

I began to tweak. 'irqtune' didnt help, 'hdparm'
with unmaskirq did nothing. MTU et al - nope.
My 'ifconfig' shows enormous serial overruns - but
this is a PII450, 2.0.36 kernel - why cant it keep
up with the port! and Im stuck! ifconfig for sl0 is
thus:

Link encap:VJ Serial Line IP  
inet addr:146.X.X.X  P-t-P:146.X.X.X
Mask:255.255.255.0
UP POINTOPOINT RUNNING  MTU:552  Metric:1
RX packets:4385 errors:0 dropped:0 overruns:3531
frame:0
   compressed:0
TX packets:2509 errors:0 dropped:0 overruns:2010
carrier:0
   Collisions:99 compressed:0

My only guess is that the modem, when doing its
internal compression of 'text' data (which compresses
well) is falling over somehow - its connecting at
33.3k,
its external (not a winmodem) - and it works fine in
connecting to the same ISP etc etc under Win98.

bert
--
-------------------------------------------------------
Linux - reaches the parts other beers fail to reach.
WWW: http://www.cms.dmu.ac.uk/~rl
WWW: http://www.ccsr.cms.dmu.ac.uk/
-------------------------------------------------------

 
 
 

Serial overruns/collisions (incoming only oddities)

Post by Robert Loga » Sat, 06 Feb 1999 04:00:00



> From PC to ISP
> 100k gzipped file (v fast)
> 100k text file (v fast)
> From ISP to PC
> 100k gzipped file (v fast)
> 100k text file (hangs - or very very slow - 0.15k/s)
> The PC's connection is via CSLIP (PPP suffers the
> same), with the port set at 115200, the IRQ is
> not in conflict, indeed, I have been using the
> same DIP script/cfgs (accounting for upgrades)
> since my 1st kernel.

I tried again - with the port set at 38400 and
then 57600 - both seem to work fine (although
overruns at 57600 were evident). But at 115200
its appalling. Is this a serial port problem?

bert

--
-------------------------------------------------------
Linux - reaches the parts other beers fail to reach.
WWW: http://www.cms.dmu.ac.uk/~rl
WWW: http://www.ccsr.cms.dmu.ac.uk/
-------------------------------------------------------

 
 
 

Serial overruns/collisions (incoming only oddities)

Post by Corey J. Steel » Thu, 11 Feb 1999 04:00:00


Have you checked to see that the initialization string to the modem is correct?
Certainly you've covered ALL other bases (shit I'd never even think of, you
threw out casually)... It may be so simple you've missed it.

Alternatively, test a different modem... see if the results are the same:
  <cheap>
        (goto Best Buy, pick one up, test it, and return it afterwards --  read
        the back of the reciept for return policies).
  </cheap>

-C


>Ive been using Win98 in my Dell XPS R450 for ages now,
>due to my inability to get linux to work with dial-up
>connections properly (win98 is fine). As a long long
>time
>linux user (pl15f 0.99 was my startpoint), I have found
>this galling, and thus decided to investigate heavily.

>I have a 100k ASCII text file ive been using since my
>1st 14.4k modem which has highlighted various speed
>improvements of my connection over time. When I got
>my new Dell and 56k modem (connecting to a 33k ISP),
>I thought i would get a reasonable throughput. The
>oddness begins.

>From PC to ISP
>100k gzipped file (v fast)
>100k text file (v fast)

>From ISP to PC
>100k gzipped file (v fast)
>100k text file (hangs - or very very slow - 0.15k/s)

>Thus, any web browsing, telnetting, or whatever is
>abysmally slow - text stuff just gets stuck. But
>any uploads, or compressed data is fine!

>The PC's connection is via CSLIP (PPP suffers the
>same), with the port set at 115200, the IRQ is
>not in conflict, indeed, I have been using the
>same DIP script/cfgs (accounting for upgrades)
>since my 1st kernel.

>I began to tweak. 'irqtune' didnt help, 'hdparm'
>with unmaskirq did nothing. MTU et al - nope.
>My 'ifconfig' shows enormous serial overruns - but
>this is a PII450, 2.0.36 kernel - why cant it keep
>up with the port! and Im stuck! ifconfig for sl0 is
>thus:

>Link encap:VJ Serial Line IP  
>inet addr:146.X.X.X  P-t-P:146.X.X.X
>Mask:255.255.255.0
>UP POINTOPOINT RUNNING  MTU:552  Metric:1
>RX packets:4385 errors:0 dropped:0 overruns:3531
>frame:0
>   compressed:0
>TX packets:2509 errors:0 dropped:0 overruns:2010
>carrier:0
>   Collisions:99 compressed:0

>My only guess is that the modem, when doing its
>internal compression of 'text' data (which compresses
>well) is falling over somehow - its connecting at
>33.3k,
>its external (not a winmodem) - and it works fine in
>connecting to the same ISP etc etc under Win98.

>bert
>--
>-------------------------------------------------------
>Linux - reaches the parts other beers fail to reach.
>WWW: http://www.cms.dmu.ac.uk/~rl
>WWW: http://www.ccsr.cms.dmu.ac.uk/
>-------------------------------------------------------

 
 
 

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shut down, what causes these dastardly things?

Thanks   (:

--

"You can always make peace with an F-16 in your pocket"
     -Yitzhak Rabin

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