[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Odd network behaviour

On Wed, Oct 02, 2002 at 11:30:07AM +0200, Russell Coker wrote:
> On Wed, 2 Oct 2002 12:15, Statu Nascendi wrote:
> > Maybe you can get through this without changing your hardware, by enqueing
> > the outgoing packets on the linux box, not on the modem.
> > This can be done using QOS - cbq or tbf (which have to be compiled in the
> > kernel or as modules) to slow down and enqueue the packets going out
> > through the ppp. You also need iproute2(tc is the program that you really
> > need) to configure the packet scheduler's behaviour. Documentation can be
> > found at http://lartc.org or http://vasile.lantech.ro/pub/Manuale/lartc.pdf
> > (the last one is saved on my computer at home but is available 24/7 and
> > you'll find some good examples there - see section, - you
> > should try this first and more examples if you really want to learn bout
> > the power embedded in the linux kernel ;)) )
> If (as I suspect) the problem is the kernel being too busy to process serial 
> port interrupts (or polling if it's really cheap hardware) then queuing 
> packets isn't going to help.  The problem will be on receiving, and it will 
> be the spacing of data within a packet.
> Using a lower serial port speed might help...

Don't forget the old reliable (adjust params to your particular situation);

hdparm -m16 -c1 -d1 -u1 /dev/hda
irqtune 3 14

Install the hwtool package and configure... This enables interupts when
processing hda interupts, allowing interleaving of serial coms with HDD
activity. It also places serial interupts at a higher priority so they get
serviced before HDD.

Note that the above hdpam settings can be risky on some hardware. I suspect
that the "-d1" which turns on DMA probably makes the other hdparm options
redundant. I have had the "-d1" trash HDD's on some MB's, but on most modern
motherboards its pretty much an essential system optimisation (huge
performance boost).

ABO: finger abo@minkirri.apana.org.au for more info, including pgp key

Reply to: