On 01/09/2013 11:32 PM, Michael S. Tsirkin wrote: > On Wed, Jan 09, 2013 at 03:29:24PM +0100, Stefan Hajnoczi wrote: >> On Fri, Dec 28, 2012 at 06:31:52PM +0800, Jason Wang wrote: >>> Perf Numbers: >>> >>> Two Intel Xeon 5620 with direct connected intel 82599EB >>> Host/Guest kernel: David net tree >>> vhost enabled >>> >>> - lots of improvents of both latency and cpu utilization in request-reponse test >>> - get regression of guest sending small packets which because TCP tends to batch >>> less when the latency were improved >>> >>> 1q/2q/4q >>> TCP_RR >>> size #sessions trans.rate norm trans.rate norm trans.rate norm >>> 1 1 9393.26 595.64 9408.18 597.34 9375.19 584.12 >>> 1 20 72162.1 2214.24 129880.22 2456.13 196949.81 2298.13 >>> 1 50 107513.38 2653.99 139721.93 2490.58 259713.82 2873.57 >>> 1 100 126734.63 2676.54 145553.5 2406.63 265252.68 2943 >>> 64 1 9453.42 632.33 9371.37 616.13 9338.19 615.97 >>> 64 20 70620.03 2093.68 125155.75 2409.15 191239.91 2253.32 >>> 64 50 106966 2448.29 146518.67 2514.47 242134.07 2720.91 >>> 64 100 117046.35 2394.56 190153.09 2696.82 238881.29 2704.41 >>> 256 1 8733.29 736.36 8701.07 680.83 8608.92 530.1 >>> 256 20 69279.89 2274.45 115103.07 2299.76 144555.16 1963.53 >>> 256 50 97676.02 2296.09 150719.57 2522.92 254510.5 3028.44 >>> 256 100 150221.55 2949.56 197569.3 2790.92 300695.78 3494.83 >>> TCP_CRR >>> size #sessions trans.rate norm trans.rate norm trans.rate norm >>> 1 1 2848.37 163.41 2230.39 130.89 2013.09 120.47 >>> 1 20 23434.5 562.11 31057.43 531.07 49488.28 564.41 >>> 1 50 28514.88 582.17 40494.23 605.92 60113.35 654.97 >>> 1 100 28827.22 584.73 48813.25 661.6 61783.62 676.56 >>> 64 1 2780.08 159.4 2201.07 127.96 2006.8 117.63 >>> 64 20 23318.51 564.47 30982.44 530.24 49734.95 566.13 >>> 64 50 28585.72 582.54 40576.7 610.08 60167.89 656.56 >>> 64 100 28747.37 584.17 49081.87 667.87 60612.94 662 >>> 256 1 2772.08 160.51 2231.84 131.05 2003.62 113.45 >>> 256 20 23086.35 559.8 30929.09 528.16 48454.9 555.22 >>> 256 50 28354.7 579.85 40578.31 607 60261.71 657.87 >>> 256 100 28844.55 585.67 48541.86 659.08 61941.07 676.72 >>> TCP_STREAM guest receiving >>> size #sessions throughput norm throughput norm throughput norm >>> 1 1 16.27 1.33 16.1 1.12 16.13 0.99 >>> 1 2 33.04 2.08 32.96 2.19 32.75 1.98 >>> 1 4 66.62 6.83 68.3 5.56 66.14 2.65 >>> 64 1 896.55 56.67 914.02 58.14 898.9 61.56 >>> 64 2 1830.46 91.02 1812.02 64.59 1835.57 66.26 >>> 64 4 3626.61 142.55 3636.25 100.64 3607.46 75.03 >>> 256 1 2619.49 131.23 2543.19 129.03 2618.69 132.39 >>> 256 2 5136.58 203.02 5163.31 141.11 5236.51 149.4 >>> 256 4 7063.99 242.83 9365.4 208.49 9421.03 159.94 >>> 512 1 3592.43 165.24 3603.12 167.19 3552.5 169.57 >>> 512 2 7042.62 246.59 7068.46 180.87 7258.52 186.3 >>> 512 4 6996.08 241.49 9298.34 206.12 9418.52 159.33 >>> 1024 1 4339.54 192.95 4370.2 191.92 4211.72 192.49 >>> 1024 2 7439.45 254.77 9403.99 215.24 9120.82 222.67 >>> 1024 4 7953.86 272.11 9403.87 208.23 9366.98 159.49 >>> 4096 1 7696.28 272.04 7611.41 270.38 7778.71 267.76 >>> 4096 2 7530.35 261.1 8905.43 246.27 8990.18 267.57 >>> 4096 4 7121.6 247.02 9411.75 206.71 9654.96 184.67 >>> 16384 1 7795.73 268.54 7780.94 267.2 7634.26 260.73 >>> 16384 2 7436.57 255.81 9381.86 220.85 9392 220.36 >>> 16384 4 7199.07 247.81 9420.96 205.87 9373.69 159.57 >>> TCP_MAERTS guest sending >>> size #sessions throughput norm throughput norm throughput norm >>> 1 1 15.94 0.62 15.55 0.61 15.13 0.59 >>> 1 2 36.11 0.83 32.46 0.69 32.28 0.69 >>> 1 4 71.59 1 68.91 0.94 61.52 0.77 >>> 64 1 630.71 22.52 622.11 22.35 605.09 21.84 >>> 64 2 1442.36 30.57 1292.15 25.82 1282.67 25.55 >>> 64 4 3186.79 42.59 2844.96 36.03 2529.69 30.06 >>> 256 1 1760.96 58.07 1738.44 57.43 1695.99 56.19 >>> 256 2 4834.23 95.19 3524.85 64.21 3511.94 64.45 >>> 256 4 9324.63 145.74 8956.49 116.39 6720.17 73.86 >>> 512 1 2678.03 84.1 2630.68 82.93 2636.54 82.57 >>> 512 2 9368.17 195.61 9408.82 204.53 5316.3 92.99 >>> 512 4 9186.34 209.68 9358.72 183.82 9489.29 160.42 >>> 1024 1 3620.71 109.88 3625.54 109.83 3606.61 112.35 >>> 1024 2 9429 258.32 7082.79 120.55 7403.53 134.78 >>> 1024 4 9430.66 290.44 9499.29 232.31 9414.6 190.92 >>> 4096 1 9339.28 296.48 9374.23 372.88 9348.76 298.49 >>> 4096 2 9410.53 378.69 9412.61 286.18 9409.75 278.31 >>> 4096 4 9487.35 374.1 9556.91 288.81 9441.94 221.64 >>> 16384 1 9380.43 403.8 9379.78 399.13 9382.42 393.55 >>> 16384 2 9367.69 406.93 9415.04 312.68 9409.29 300.9 >>> 16384 4 9391.96 405.17 9695.12 310.54 9423.76 223.47 >> Trying to understand the performance results: >> >> What is the host device configuration? tap + bridge? Yes. >> >> Did you use host CPU affinity for the vhost threads? I use numactl to pin cpu threads and vhost threads in the same numa node. >> Can multiqueue tap take advantage of multiqueue host NICs or is >> virtio-net multiqueue unaware of the physical NIC multiqueue >> capabilities? Tap is unware of the physical multiqueue NIC, but we can benefit from it since we use multiple vhost threads. >> >> The results seem pretty mixed - as a user it's not obvious what to >> choose as a good all-round setting. > Yes, this I think is the reason it's disabled by default ATM, > guest admin has to enable it using ethtool. > > From what I saw, it looks like with a streaming guest to external > benchmark, we sometimes get smaller packets and > so worse performance. We are still investigating - what's > going on seems to be a strange interaction with guest TCP stack. Yes, guest TCP tends to batch less when the multiqueue is enabled (latency is improved). So much more smaller packets were sent in this case leads to bad performance. > Other workloads seem to benefit. > >> Any observations on how multiqueue >> should be configured? > I think the right thing to do is to enable it on the host and > let guest admin enable it if appropriate. > >> What is the "norm" statistic? Sorry for not being clear, it's short for normalized result (divide the result by cpu utilization). >> Stefan > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
