Hal Murray <[EMAIL PROTECTED]> wrote: > Some Ethernet adapters have a bug/feature similar to RS-232 chips. The > idea is to batch interrupts to reduce overhead. Ethernets do it by > only making one interrupt for several packets as compared to several > bytes for the RS-232 chips.
> I'd expect gigabit cards/chips will be more likely to have that > feature than old "slow" 100 megabit chips. Virtually all the GbE NICs I've ever encountered have such a feature. And literally all the 10 GbE NCIs I've encountered have it. You can see such behaviour in a NIC/driver which does it "badly" (IMO) with a netperf TCP_RR test. For example if you only ever see 8000-12000 single-byte transactions per second with a "contemporary" system. A while back I did a writeup on the tradeoff the NIC/driver strappings were making. A version of it can be found at: ftp://ftp.cup.hp.com/dist/networking/briefs/nic_latency_vs_tput.txt Not all NIC/driver combinations do it as badly as others. I've encountered at least one, perhaps two 10GbE NICs which seem to at least pass the TCP_RR sniff test and get both good TCP_RR performance and good CPU util on TCP_STREAM with defaults. rick jones -- oxymoron n, commuter in a gas-guzzling luxury SUV with an American flag these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH... _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
