IRQ, network drivers, and the like...

[Chris Newton]

Yup, Im quite sure of the packet rate.

  Source 1 was argus, showed about 10K (5 in/out)
  Source 2 was Sniffer, showed same, 10K
  Source 3 was laptop hooked to terminal port of the hub that the traffic is 
monitored on... showed 5K in port 1, 5K in port 2, all mirrored and exiting 
out port 3 at 10K.  No other ports in use on the hub. (ie: ports 1 and 2 are 
both sides of a 100 Mbit ocnnection)

  right now, the traffic is starting to lower (later in the day now)... her 
eis 'procinfo -D' output:

irq  0:       500 timer                 irq 14:         0 ide0
irq  1:         0 keyboard              irq 16:       360 eth2
irq  2:         0 cascade [4]           irq 20:     23804 eth0
irq  3:         0                       irq 21:         0 eth1
irq  4:         0                       irq 30:        72 aic7xxx
irq  6:         0                       irq 31:       202 aic7xxx
irq 12:         0




Chris

>===== Original Message From Peter Van Epp <vanepp at sfu.ca> =====
>	1 interrupt per packet would be my impression too. Are you sure of the
>input packet rate (i.e. is the packet count the same from an rmon capable
>network device connected to the same network)? Things to look at would be DNS
>lookups being done per packet (such as if ra is reading the data stream as it
>rolls by) from the same network, and argus running out the same interface as 
a
>network server (although the packet rate from that should be much lower
>that the input stream rate). Something may be generating extra traffic you
>haven't accounted for. A tcpdump from a second machine would be interesting
>to see what and how many packets it thinks are being delivered (or an rmon
>capable device as I said). We always use 3c509s, I don't know if Martin has
>experimented with 3c59x cards. 3 3c509s in a dual processor machine (with
>I think Mr Becker's link aggregating drivers) can get 294 megs per second
>between machines in a beowolf cluster. That eats one entire CPU for the
>network between interrupts and stack processing leaving the other CPU for
>doing useful work so you just need to accept that the net is likely to need
>to eat an entire CPU and not much is going to help that. The 3c905s are the
>fastest cards we have found (the Etherexpress is a small fraction slower).
>
>Peter Van Epp / Operations and Technical Support
>Simon Fraser University, Burnaby, B.C. Canada
>
>
>>
>> Yup, 30k interrupts/second.
>>
>>   Well, I had a brief discussion with Donald Becker, who had written most 
of
>> the linux network drivers, and he thought this was weird, and indicated a
>> problem.  He thought the card(s) I was using should generate slightly less
>> then the number of TX/RX packets/second.
>>
>>   Problem is, after sending him some info, he seems to have dropped away 
for a
>> while.  Likely on vacation or something... mmmmm.... vacation :)
>>
>>   What are other people's experiences with the 3com 3c59x class of cards?
>> Does 30K interrupts sound reasonable for 10K packets?
>>
>>   Is this high?  IE: is this affecting system performance for other 
devices?
>> Should I invest in a better card(s) with interrupt coallecing (sp?)?
>>
>> Thanks
>>
>> Chris
>>
>>
>> >===== Original Message From <carter at qosient.com> =====
>> >Hey Chris,
>> >   Do you mean interrupts per second?  I can understand how the
>> >card could generate (3 x (the number of packet)) interrupts.
>> >Start of bus transfer, end of bus transfer, and specific device
>> >handler interrupt, but this is just a guess, I don't really
>> >know.  Possibly Peter will have a real educated guess as to
>> >what is going on, and knowing him, possibly a way around it.
>> >
>> >Carter
>> >
>> >Carter Bullard
>> >QoSient, LLC
>> >300 E. 56th Street, Suite 18K
>> >New York, New York  10022
>> >
>> >carter at qosient.com
>> >Phone +1 212 588-9133
>> >Fax   +1 212 588-9134
>> >http://qosient.com
>> >
>> >> -----Original Message-----
>> >> From: Chris Newton [mailto:newton at unb.ca]
>> >> Sent: Tuesday, September 25, 2001 1:57 PM
>> >> To: carter at qosient.com
>> >> Subject: IRQ, network drivers, and the like...
>> >>
>> >>
>> >> Hi Carter,  how have you been?
>> >>
>> >>   I'm struggling with a weird problem and I thought maybe you
>> >> might have seen
>> >> this before, or be able to point me in the right direction.
>> >>
>> >>   One of the networks I'm watching (my big network), has (for
>> >> example), about
>> >> 5000 incoming packets and 5000 outgoing right now... works
>> >> out to about 2MB in
>> >> both directions.  That is fed into an argus box, via 1
>> >> cable... so, 10K
>> >> packets per second on the cable.
>> >>
>> >>   Whats weird.. is that right now, my network card is
>> >> generating about 26 to
>> >> 30,000 packets/second.  I feel this is bogging the machine...
>> >> and I dont know
>> >> why it might be doing that.  Argus is running, reading from
>> >> that interface.
>> >>
>> >>   The card is a 3Com, 3c980 (or something)... but, Im not
>> >> sure that matters...
>> >> because I swapped it for a intel etherner express pro, and I
>> >> had the same
>> >> problem... (even higher actually).  There is also an ra
>> >> client reading from
>> >> the localargus stream.
>> >>
>> >>   Weird.. but, do you have any ideas?
>> >>
>> >>
>>
>>