Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH net-next v2 4/4] net: mvneta: Spread out the TX queues management on all CPUs | Date | Fri, 04 Dec 2015 22:30:35 +0100 |
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On Friday 04 December 2015 11:12:30 Eric Dumazet wrote: > On Fri, 2015-12-04 at 19:45 +0100, Gregory CLEMENT wrote: > > With this patch each CPU is associated with its own set of TX queues. In > > the same time the SKB received in mvneta_tx is bound to the queue > > associated to the CPU sending the data. Thanks to this the next IRQ will > > be received on the same CPU allowing sending more data. > > > > It will also allow to have a more predictable behavior regarding > > throughput and latency when having multiple threads sending out data on > > different CPUs. > > > > As an example on Armada XP GP, with an iperf bound to a CPU and a ping > > bound to another CPU, without this patch the ping round trip was about > > 2.5ms (and could reach 3s!), whereas with this patch it was around > > 0.7ms (and sometime it went to 1.2ms). > > This really looks like you need something smarter than pfifo_fast qdisc, > and maybe BQL (I did not check if this driver already implements this)
I suggested this change as well as the BQL implementation that Marcin did. I believe he hasn't posted that yet while he's doing some more testing, but it should come soon.
Arnd
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