Messages in this thread | | | Subject | RE: arm: Optimization for ethernet MAC handling at91_ether.c | Date | Tue, 12 Jan 2010 12:51:57 -0500 | From | "James Kosin" <> |
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On 1/12/2010 11:40 AM, Eric Dumazet wrote: > CC to netdev > > Le 12/01/2010 16:39, James Kosin a écrit : >> Everyone, >> >> Since, a AT91_EMAC_TUND only happens when the transmitter is unable to >> transfer the frame in time for a frame to be sent. It makes sense to >> RETRY the packet in this condition in the ISR. >> Or would this overcomplicate a simple task? >> ... see below ... >> > ... > >> >> ... >> I do know there needs to be a bit more code then to handle the >> successful case below this; but, this is enough to understand what I am >> talking about. The UNDERRUN error should happen infrequently and in >> ideal circumstances not happen at all. >> > > > If this happens once in a while, why do you want driver to retry the transmit ?
(a) It would improve performance by allowing the ISR to handle the re-transmit in this case. (b) It would help in the case of small glitches that may happen from external SDRAM without taxing the polling required to handle the re-transmit of the packet... ie: overhead required to re-queue and initiate a packet delivery... since the packet is already scheduled for delivery now.
James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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