From: David S. Miller Date: Thu, 29 Aug 2013 05:18:52 +0000 (-0400) Subject: Merge branch 'xen-netback' X-Git-Tag: v3.12-rc1~132^2~165 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=823a19e0cfee2ea4cacd4976730f34151481e7ac;p=~emulex%2Finfiniband.git Merge branch 'xen-netback' Wei Liu says: ==================== xen-netback: switch to NAPI + kthread 1:1 model This series implements NAPI + kthread 1:1 model for Xen netback. This model - provides better scheduling fairness among vifs - is prerequisite for implementing multiqueue for Xen network driver The second patch has the real meat: - make use of NAPI to mitigate interrupt - kthreads are not bound to CPUs any more, so that we can take advantage of backend scheduler and trust it to do the right thing Benchmark is done on a Dell T3400 workstation with 4 cores, running 4 DomUs. Netserver runs in Dom0. DomUs do netperf to Dom0 with following command: /root/netperf -H Dom0 -fm -l120 IRQs are distributed to 4 cores by hand in the new model, while in the old model vifs are automatically distributed to 4 kthreads. * New model %Cpu0 : 0.5 us, 20.3 sy, 0.0 ni, 28.9 id, 0.0 wa, 0.0 hi, 24.4 si, 25.9 st %Cpu1 : 0.5 us, 17.8 sy, 0.0 ni, 28.8 id, 0.0 wa, 0.0 hi, 27.7 si, 25.1 st %Cpu2 : 0.5 us, 18.8 sy, 0.0 ni, 30.7 id, 0.0 wa, 0.0 hi, 22.9 si, 27.1 st %Cpu3 : 0.0 us, 20.1 sy, 0.0 ni, 30.4 id, 0.0 wa, 0.0 hi, 22.7 si, 26.8 st Throughputs: 2027.89 2025.95 2018.57 2016.23 aggregated: 8088.64 * Old model %Cpu0 : 0.5 us, 68.8 sy, 0.0 ni, 16.1 id, 0.5 wa, 0.0 hi, 2.8 si, 11.5 st %Cpu1 : 0.4 us, 45.1 sy, 0.0 ni, 31.1 id, 0.4 wa, 0.0 hi, 2.1 si, 20.9 st %Cpu2 : 0.9 us, 44.8 sy, 0.0 ni, 30.9 id, 0.0 wa, 0.0 hi, 1.3 si, 22.2 st %Cpu3 : 0.8 us, 46.4 sy, 0.0 ni, 28.3 id, 1.3 wa, 0.0 hi, 2.1 si, 21.1 st Throughputs: 1899.14 2280.43 1963.33 1893.47 aggregated: 8036.37 We can see that the impact is mainly on CPU usage. The new model moves processing from kthread to NAPI (software interrupt). ==================== Signed-off-by: David S. Miller --- 823a19e0cfee2ea4cacd4976730f34151481e7ac