Messages in this thread |  | | Date | Fri, 15 Sep 2000 16:53:21 +0200 (CEST) | From | Bogdan Costescu <> |
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On Fri, 15 Sep 2000, jamal wrote:
> Only the timer runs at HZ granularity ;-<
Some cards provide their own high resolution timers; latest 3Com cards provide several with different purposes (none currently used). The question is how many of these also provide the Rx early interrupts. You also mentioned an auto-tunable Rx mitigation scheme. How do you implement it without using hardware timers ?
> 20Msec is probably too much time. If my math is not wrong, 1 bit time in > a 100Mps is 1 ns; 64 bytes is 512ns.
I think your are wrong by a factor of 10 here, 1 bit time at 100Mbps should be 10 ns. Then 64 bytes is 5.12 us (u=micro). Anyway, this is comparable with the time needed to reach ISR, so you can have several (but small number) of packets already waiting for processing.
> You use the period(5-10micros), while waiting > for full packet arrival, to make the route decision (lookup etc). > i.e this will allow for a better FF; it will not offload things.
Just that you span several layers by doing this, it's not driver specific anymore.
Sincerely,
Bogdan Costescu
IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868 E-mail: Bogdan.Costescu@IWR.Uni-Heidelberg.De
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