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On Thu, 13 Nov 2008, David Miller wrote: > From: Jesper Dangaard Brouer <jdb@comx.dk> > Date: Thu, 13 Nov 2008 11:29:31 +0100 > >> Although I'm not happy about the new perf numbers, as I now on a SMP >> system only can route approx 290 kpps, remember I could route 319 kpps >> using a single CPU nosmp kernel. > > That unfortunately (can be) the cost of SMP :-/ [Regression] Well that was not the real cause of the performance loss. Because on kernel 2.6.27 I get really good performance (900-1200kpps) compared to 2.6.28 (git net-2.6). The cause of this problem (tracked down together with Robert Olsson) is that on 2.6.28 I have a lot less IRQs available. It seems max 34 IRQs. Due the reduced number of IRQs the NIU driver cannot get enough IRQs to the interfaces, and starts to use "IO-APIC" based IRQs. On kernel 2.6.28: My eth2 is using 10 IRQs all "PCI-MSI-edge". BUT my eth3 is using a single IRQ using "IO-APIC-fasteoi" and shared with the usb driver... Think thats must be my performance problem on 2.6.28. > With multi-flow tests, Robert Olsson is getting 4.2 mpps rates with > NIU and pktgen. That's what this card is designed for, good > multi-flow workload performance, rather than striving for maximum > single-flow performance. [Packet performance] Yes, I know, I do use pktgen and multi-flows (rand dest IP+port). For the two drivers NIU and Suns NXGE, my packet per sec performance is now, on 2.6.27 (with backported NIU fixes). With NIU driver I can route 900 kpps. With NXGE driver (and enqueue=NULL hack) I can route 1200 kpps. Actually I think I can go higher, because I'm limited by my packet rate generator. I use pktgen (with rand dst IP+port) and can only generate 1200 kpps. (I have actually ordered some new hardware, so I can get a faster pktgen machine and perhaps test it as a router too. Also ordered the hardware because I want to test PCI-express v.2.0. I have a prototype 12-port gigabit NIC (from hotlava systems) that support PCIe v.2.0 and has 6x 82575 chips (4RX/4TX queues)) Hilsen Jesper Brouer -- ------------------------------------------------------------------- MSc. Master of Computer Science Dept. of Computer Science, University of Copenhagen Author of http://www.adsl-optimizer.dk ------------------------------------------------------------------- | ||||||||||
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