As my test results showed in this thread. 1. Zswap only useful when total ram size is large else the performance was worse than disabled it! 2. Zswap occupies some memory but that's unfair to file pages, more file pages maybe reclaimed during memory pressure. I think that's why the performance of the background io-duration was worse than disable zswap. Seth, any feedback? Do you observe the same issue? On Thu, Jun 27, 2013 at 10:03 AM, Bob Liu <lliubbo@xxxxxxxxx> wrote: > Hi All, > > These days I have been testing zswap. > I found that the total ram size of my testing machine effected the > testing result. > > If I limit RAM size to 2G using "mem=", the performance of zswap is > very disappointing, > But if I use larger RAM size such as 8G, the performance is much better. > Even with RAM size 8G, zswap will slow down the speed of parallelio. > > I run the testing(mmtest-0.10 with > config-global-dhp__parallelio-memcachetest) after the default > distribution booted every time. > > Below are some results: > > 1) kernel verion 3.10-rc6, mem=2G > > parallelio > rc6 rc6 > base-2G zswap-2G > Ops memcachetest-0M 14719.00 ( 0.00%) 10617.00 (-27.87%) > Ops memcachetest-200M 14711.00 ( 0.00%) 10152.00 (-30.99%) > Ops memcachetest-433M 14839.00 ( 0.00%) 10245.00 (-30.96%) > Ops memcachetest-666M 14989.00 ( 0.00%) 10134.00 (-32.39%) > Ops memcachetest-900M 15180.00 ( 0.00%) 9821.00 (-35.30%) > Ops memcachetest-1133M 15654.00 ( 0.00%) 9178.00 (-41.37%) > Ops memcachetest-1367M 16100.00 ( 0.00%) 9740.00 (-39.50%) > Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) > Ops io-duration-200M 3.00 ( 0.00%) 5.00 (-66.67%) > Ops io-duration-433M 6.00 ( 0.00%) 10.00 (-66.67%) > Ops io-duration-666M 10.00 ( 0.00%) 14.00 (-40.00%) > Ops io-duration-900M 13.00 ( 0.00%) 21.00 (-61.54%) > Ops io-duration-1133M 17.00 ( 0.00%) 25.00 (-47.06%) > Ops io-duration-1367M 20.00 ( 0.00%) 31.00 (-55.00%) > Ops swaptotal-0M 39.00 ( 0.00%) 81481.00 > (-208825.64%) > Ops swaptotal-200M 1400.00 ( 0.00%) 106825.00 (-7530.36%) > Ops swaptotal-433M 16.00 ( 0.00%) 103052.00 > (-643975.00%) > Ops swaptotal-666M 8.00 ( 0.00%) 93693.00 > (-1171062.50%) > Ops swaptotal-900M 0.00 ( 0.00%) 91009.00 (-99.00%) > Ops swaptotal-1133M 3609.00 ( 0.00%) 103650.00 (-2771.99%) > Ops swaptotal-1367M 95.00 ( 0.00%) 89652.00 > (-94270.53%) > Ops swapin-0M 39.00 ( 0.00%) 39283.00 > (-100625.64%) > Ops swapin-200M 678.00 ( 0.00%) 50220.00 (-7307.08%) > Ops swapin-433M 16.00 ( 0.00%) 48372.00 > (-302225.00%) > Ops swapin-666M 8.00 ( 0.00%) 43669.00 > (-545762.50%) > Ops swapin-900M 0.00 ( 0.00%) 42791.00 (-99.00%) > Ops swapin-1133M 716.00 ( 0.00%) 49320.00 (-6788.27%) > Ops swapin-1367M 91.00 ( 0.00%) 42094.00 > (-46157.14%) > Ops minorfaults-0M 511226.00 ( 0.00%) 532594.00 ( -4.18%) > Ops minorfaults-200M 507501.00 ( 0.00%) 577895.00 (-13.87%) > Ops minorfaults-433M 507342.00 ( 0.00%) 573211.00 (-12.98%) > Ops minorfaults-666M 506917.00 ( 0.00%) 565424.00 (-11.54%) > Ops minorfaults-900M 513814.00 ( 0.00%) 569420.00 (-10.82%) > Ops minorfaults-1133M 559981.00 ( 0.00%) 592414.00 ( -5.79%) > Ops minorfaults-1367M 511420.00 ( 0.00%) 572809.00 (-12.00%) > Ops majorfaults-0M 6.00 ( 0.00%) 8593.00 > (-143116.67%) > Ops majorfaults-200M 200.00 ( 0.00%) 11335.00 (-5567.50%) > Ops majorfaults-433M 55.00 ( 0.00%) 10729.00 > (-19407.27%) > Ops majorfaults-666M 68.00 ( 0.00%) 9258.00 > (-13514.71%) > Ops majorfaults-900M 94.00 ( 0.00%) 9935.00 > (-10469.15%) > Ops majorfaults-1133M 411.00 ( 0.00%) 10902.00 (-2552.55%) > Ops majorfaults-1367M 133.00 ( 0.00%) 9340.00 (-6922.56%) > > rc6 rc6 > base-2G zswap-2G > User 1068.98 715.36 > System 3910.06 2696.03 > Elapsed 7871.94 7890.20 > > rc6 rc6 > base-2G zswap-2G > Page Ins 1322220 10206472 > Page Outs 24675096 31069608 > Swap Ins 100636 1548495 > Swap Outs 134568 1734841 > Direct pages scanned 14441 16430214 > Kswapd pages scanned 7792848 35445764 > Kswapd pages reclaimed 6486627 7514907 > Direct pages reclaimed 4342 2166004 > Kswapd efficiency 83% 21% > Kswapd velocity 989.953 4492.378 > Direct efficiency 30% 13% > Direct velocity 1.834 2082.357 > Percentage direct scans 0% 31% > Page writes by reclaim 135881 5002899 > Page writes file 1313 3268058 > Page writes anon 134568 1734841 > Page reclaim immediate 111 8048646 > Page rescued immediate 0 0 > Slabs scanned 1532032 8295040 > > 2) kernel verion 3.10-rc6, mem=8G > parallelio > rc6 rc6 > base-8G zswap-8G > Ops memcachetest-0M 16298.00 ( 0.00%) 15496.00 ( -4.92%) > Ops memcachetest-773M 13594.00 ( 0.00%) 12175.00 (-10.44%) > Ops memcachetest-1675M 5937.00 ( 0.00%) 8520.00 ( 43.51%) > Ops memcachetest-2577M 5972.00 ( 0.00%) 8378.00 ( 40.29%) > Ops memcachetest-3479M 2810.00 ( 0.00%) 3422.00 ( 21.78%) > Ops memcachetest-4381M 3579.00 ( 0.00%) 2760.00 (-22.88%) > Ops memcachetest-5284M 2266.00 ( 0.00%) 2166.00 ( -4.41%) > Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) > Ops io-duration-773M 16.00 ( 0.00%) 18.00 (-12.50%) > Ops io-duration-1675M 34.00 ( 0.00%) 51.00 (-50.00%) > Ops io-duration-2577M 46.00 ( 0.00%) 55.00 (-19.57%) > Ops io-duration-3479M 64.00 ( 0.00%) 82.00 (-28.12%) > Ops io-duration-4381M 77.00 ( 0.00%) 102.00 (-32.47%) > Ops io-duration-5284M 91.00 ( 0.00%) 128.00 (-40.66%) > Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%) > Ops swaptotal-773M 86867.00 ( 0.00%) 64298.00 ( 25.98%) > Ops swaptotal-1675M 258889.00 ( 0.00%) 119483.00 ( 53.85%) > Ops swaptotal-2577M 249005.00 ( 0.00%) 110535.00 ( 55.61%) > Ops swaptotal-3479M 317495.00 ( 0.00%) 177709.00 ( 44.03%) > Ops swaptotal-4381M 239539.00 ( 0.00%) 166971.00 ( 30.29%) > Ops swaptotal-5284M 286595.00 ( 0.00%) 154143.00 ( 46.22%) > Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%) > Ops swapin-773M 39739.00 ( 0.00%) 31843.00 ( 19.87%) > Ops swapin-1675M 128380.00 ( 0.00%) 59499.00 ( 53.65%) > Ops swapin-2577M 115923.00 ( 0.00%) 55016.00 ( 52.54%) > Ops swapin-3479M 143563.00 ( 0.00%) 87498.00 ( 39.05%) > Ops swapin-4381M 115248.00 ( 0.00%) 77465.00 ( 32.78%) > Ops swapin-5284M 120546.00 ( 0.00%) 61451.00 ( 49.02%) > Ops minorfaults-0M 1526324.00 ( 0.00%) 1521203.00 ( 0.34%) > Ops minorfaults-773M 1592495.00 ( 0.00%) 1581814.00 ( 0.67%) > Ops minorfaults-1675M 1652153.00 ( 0.00%) 1603339.00 ( 2.95%) > Ops minorfaults-2577M 1648158.00 ( 0.00%) 1596046.00 ( 3.16%) > Ops minorfaults-3479M 1581514.00 ( 0.00%) 1562471.00 ( 1.20%) > Ops minorfaults-4381M 1587579.00 ( 0.00%) 1526344.00 ( 3.86%) > Ops minorfaults-5284M 1540904.00 ( 0.00%) 1506546.00 ( 2.23%) > Ops majorfaults-0M 0.00 ( 0.00%) 0.00 ( 0.00%) > Ops majorfaults-773M 5371.00 ( 0.00%) 5562.00 ( -3.56%) > Ops majorfaults-1675M 16701.00 ( 0.00%) 10265.00 ( 38.54%) > Ops majorfaults-2577M 14799.00 ( 0.00%) 9205.00 ( 37.80%) > Ops majorfaults-3479M 18279.00 ( 0.00%) 14593.00 ( 20.17%) > Ops majorfaults-4381M 14562.00 ( 0.00%) 12985.00 ( 10.83%) > Ops majorfaults-5284M 15177.00 ( 0.00%) 10454.00 ( 31.12%) > > rc6 rc6 > base-8G zswap-8G > User 538.84 606.68 > System 2192.36 2449.63 > Elapsed 8569.89 8601.77 > > rc6 rc6 > base-8G zswap-8G > Page Ins 12122756 6361132 > Page Outs 107059860 99973488 > Swap Ins 2973693 1536266 > Swap Outs 3489272 1716774 > Direct pages scanned 0 8914107 > Kswapd pages scanned 25711001 11516911 > Kswapd pages reclaimed 13957707 5221461 > Direct pages reclaimed 0 8848421 > Kswapd efficiency 54% 45% > Kswapd velocity 3000.155 1338.900 > Direct efficiency 100% 99% > Direct velocity 0.000 1036.311 > Percentage direct scans 0% 43% > Page writes by reclaim 6587157 3306649 > Page writes file 3097885 1589875 > Page writes anon 3489272 1716774 > Page reclaim immediate 25168 61862 > Page rescued immediate 0 0 > Slabs scanned 4218112 3148672 > Direct inode steals 0 0 > Kswapd inode steals 252 0 > Kswapd skipped wait 0 0 > -- Regards, --Bob -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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