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Date: Wed, 8 Oct 2014 19:51:26 -0400 From: Sowmini Varadhan <sowmini.varadhan@...cle.com> To: davem@...emloft.net, Raghuram.Kothakota@...cle.com Cc: netdev@...r.kernel.org Subject: Re: sunvnet and ->xmit_more One thought occurred to me about a way to use this.. It's true that in the case of sunvnet, we send the tx-trigger at the *start* of a burst, thus we would do the same amount of work whether we had 1 or N (>1) packets for a burst, until a STOPPED was received, and if we tried playing games with this, for every sequence where the game-playing around "when should I send START" helps, there would always be a counter-example where it would hurt.. but there *is* one way in which it could be used- if the producer could somehow signal the "xmit_more" info to the consumer, then the consumer could factor that information in, when trying to decide whether or not to declare STOPPED (recall the discussion around the fudge-factor that we had earlier in http://www.spinics.net/lists/netdev/msg294549.html - the skb_more provides a better hint than merely guessing a udelay) Raghuram just pointed out to me " But this can only be used as a hint, as we cannot rely on the peer to send the next pack in specific time frame, the peer may be stuck in something else or switched out due to scheduling or some bug etc. To pass this hint, .. we could use a bit in a descriptor in TxDring too." That might be worth investigating (but I might not get to it till I get the NAPI on its way). --Sowmini -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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