Duncan Sands ([EMAIL PROTECTED]) wrote:
> > Second question (see [1]):
> > In my logs the hotplug even  manager loads the speedtch driver trice.  I
> > don't  know why.   The problem  is it  fires up  3 modem_run.  Thanks to
> > modem_runs design, only one  instance finishes the initialization. Isn't
> > there a better solution ?
> 
> This is due to a usb change in the kernel: it now (since 2.4.2x, x = something) it
> launches hotplug for every interface, not each device.  This is in line with 2.5
> behaviour.  However, unlike for 2.5, the kernel does not export info about which
> interface hotplug is being called for.  I guess it is possible to work around this 
> using
> lock files storing pids and all that jazz.  One day I will send in a kernel patch to
> export the extra info, it is on my infinite TODO list...  In practice it doesn't 
> matter.

That's what i guessed. Thanks for the complete answer.

> > Third question: I'm not sure  the pppd launch belongs to the hotplug
> > event manager.  Hotplug is run  before any network services,  so the
> > connection would be  done before any firewall would  be up... As you
> > see it's not really a question, just a loud thought ;-)
> 
> It is convenient  though.  You could launch pppd in  an init script of
> course and it wouldn't make  much difference, except if you replug the
> modem.  By  the way, won't your  firewall barf if ppp0  does not exist
> when you try to do (example) masquerading with it?

No,  I've never  seen  a  firewall complaining  about  rules applied  on
unknown interfaces.  It  would be a clear implementation  flaw if it did
so, as it's good(tm) to prepare rules before the interface is up :-)

Btw if  you include  a ppp  interface upping stage  in this  script, you
have  to include a  ppp interface  downing stage,  otherwise the  ISP is
just    not   aware    of   your    disconnection   through    the   PPP
communication. This  was a  cause of problems  in early aDSL  days where
IPs  were allocated  and  never freed  in  the ISP  side. Nowadays  this
problem is no more afaik.

> > Fourth  question:  I noticed  very  CPU  usage  during network  load
> > (around 5%[2]) for a 512kbps  download. I'm not sure this is correct
> > as pppoa3 does  use much less CPU  (with 5% CPU, i can  read a mpeg4
> > movie, and i'm _sure_ mpeg4 decoding is much more CPU intensive than
> > simple memoves and usb urbs submissions) Is it normal ?
> 
> No, it is  not normal.  How are you monitoring  CPU usage?  Just using
> top, for example, won't show you any info about what's going on in the
> kernel, because it all happens  in softirq's.  You need oprofile to do
> that.  Is it pppd that is using up  the CPU?  Do you have a uhci hc by
> the way (the  driver is inefficient, but that should  be the same with
> pppoax)?  I also  have an Athlon 2200+, and  the speedtouch code comes
> up pretty  far down  the list  in my profiles  (uhci-hcd is  much more
> present though).  If you turned  on verbose debugging, the logging may
> be using  up CPU.  Try decreasing  the buffer sizes (this  is a module
> parameter) -  if that helps then you  are being hit by  the uhci hcd's
> design problems.  Also, if you  are using multiple urb support (module
> parameter) with  a 2.4  kernel then turn  it off  - it has  never been
> reliable with 2.4.  Which kernel are you running?

Yeah i used top or visually looking at gkrellm (i know it's not a great
monitor for this kind of thing)

I use a 2.4.22-ck2 kernel with preempt and low scheduling turned on. And
i'm  using the  kernel module  in  its simplest  form as  i let  hotplug
loading it  up the way it  wants and i  don't have module entries  in my
module.conf concerning speedtch.

-- 
Edouard Gomez


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