Messages in this thread | | | Date | Fri, 13 Mar 2009 17:24:10 -0700 | Subject | Re: [RFC v2: Patch 1/3] net: hand off skb list to other cpu to submit to upper layer | From | Tom Herbert <> |
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>> I appreciate this philosophy, but unfortunately I don't have the >> luxury of working with a NIC that solves these problems. The reality >> may be that we're trying to squeeze performance out of crappy hardware >> to scale on multi-core. Left alone we couldn't get the stack to >> scale, but with these "destable hacks" we've gotten 3X or so > ^^^^^^^^ > > Spelling. > >> improvement in packets per second across both our dumb 1G and 10G >> NICs > > Do these NICs at least support multiqueue? >
Yes, we are using a 10G NIC that supports multi-queue. The number of RX queues supported is half the number of cores on our platform, so that is going to limit the parallelism. With multi-queue turned on we do see about 4X improvement in pps over just using a single queue; this is about the same improvement we see using a single queue with our software steering techniques (this particular device provides the Toeplitz hash). Enabling HW multi-queue has somewhat higher CPU utilization though, the extra device interrupt load is not coming for free. We actually use the HW multi-queue in conjunction with our software steering to get maximum pps (about 20% more).
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