On Mon, 17 Jun 2013 14:20:05 +0800 Bob Liu <lliubbo@xxxxxxxxx> wrote: > Hi Seth, > > On Tue, Jun 4, 2013 at 4:33 AM, Seth Jennings > <sjenning@xxxxxxxxxxxxxxxxxx> wrote: > > zswap is a thin backend for frontswap that takes pages that are in the process > > of being swapped out and attempts to compress them and store them in a > > RAM-based memory pool. This can result in a significant I/O reduction on the > > swap device and, in the case where decompressing from RAM is faster than > > reading from the swap device, can also improve workload performance. > > > > It also has support for evicting swap pages that are currently compressed in > > zswap to the swap device on an LRU(ish) basis. This functionality makes zswap a > > true cache in that, once the cache is full, the oldest pages can be moved out > > of zswap to the swap device so newer pages can be compressed and stored in > > zswap. > > > > This patch adds the zswap driver to mm/ > > > > Do you have any more benchmark can share with me ? To figure out that > we can benefit from zswap. > > I found zswap will cause performance drop when using mmtests-0.10 to test it. > The config file I'm using is: config-global-dhp__parallelio-memcachetest Thanks for testing. > The result is: > (v3.10-rc4-2G-nozswap was without zswap but the performance is better.) > > v3.10-rc4 v3.10-rc4 > 2G-zswap-base 2G-nozswap > Ops memcachetest-0M 604.00 ( 0.00%) 1077.00 ( 78.31%) > Ops memcachetest-198M 630.00 ( 0.00%) 1007.00 ( 59.84%) > Ops memcachetest-430M 609.00 ( 0.00%) 939.00 ( 54.19%) > Ops memcachetest-661M 604.00 ( 0.00%) 845.00 ( 39.90%) > Ops memcachetest-893M 591.00 ( 0.00%) 839.00 ( 41.96%) > Ops memcachetest-1125M 599.00 ( 0.00%) 781.00 ( 30.38%) > Ops memcachetest-1356M 588.00 ( 0.00%) 771.00 ( 31.12%) > Ops io-duration-0M 0.00 ( 0.00%) 1.00 (-99.00%) > Ops io-duration-198M 177.00 ( 0.00%) 21.00 ( 88.14%) > Ops io-duration-430M 168.00 ( 0.00%) 25.00 ( 85.12%) > Ops io-duration-661M 214.00 ( 0.00%) 30.00 ( 85.98%) > Ops io-duration-893M 186.00 ( 0.00%) 32.00 ( 82.80%) > Ops io-duration-1125M 175.00 ( 0.00%) 42.00 ( 76.00%) > Ops io-duration-1356M 245.00 ( 0.00%) 51.00 ( 79.18%) > Ops swaptotal-0M 487760.00 ( 0.00%) 459754.00 ( 5.74%) > Ops swaptotal-198M 563581.00 ( 0.00%) 485194.00 ( 13.91%) > Ops swaptotal-430M 579472.00 ( 0.00%) 500817.00 ( 13.57%) > Ops swaptotal-661M 568086.00 ( 0.00%) 524209.00 ( 7.72%) > Ops swaptotal-893M 584405.00 ( 0.00%) 509846.00 ( 12.76%) > Ops swaptotal-1125M 572992.00 ( 0.00%) 534115.00 ( 6.78%) > Ops swaptotal-1356M 573259.00 ( 0.00%) 529814.00 ( 7.58%) > Ops swapin-0M 231250.00 ( 0.00%) 236069.00 ( -2.08%) > Ops swapin-198M 312259.00 ( 0.00%) 239149.00 ( 23.41%) > Ops swapin-430M 327178.00 ( 0.00%) 246803.00 ( 24.57%) > Ops swapin-661M 319575.00 ( 0.00%) 273644.00 ( 14.37%) > Ops swapin-893M 328195.00 ( 0.00%) 257327.00 ( 21.59%) > Ops swapin-1125M 317345.00 ( 0.00%) 271109.00 ( 14.57%) > Ops swapin-1356M 312858.00 ( 0.00%) 266050.00 ( 14.96%) > Ops minorfaults-0M 592150.00 ( 0.00%) 646076.00 ( -9.11%) > Ops minorfaults-198M 637339.00 ( 0.00%) 676441.00 ( -6.14%) > Ops minorfaults-430M 626228.00 ( 0.00%) 684715.00 ( -9.34%) > Ops minorfaults-661M 625089.00 ( 0.00%) 670639.00 ( -7.29%) > Ops minorfaults-893M 612877.00 ( 0.00%) 669723.00 ( -9.28%) > Ops minorfaults-1125M 624800.00 ( 0.00%) 667025.00 ( -6.76%) > Ops minorfaults-1356M 618800.00 ( 0.00%) 657600.00 ( -6.27%) > Ops majorfaults-0M 67664.00 ( 0.00%) 40060.00 ( 40.80%) > Ops majorfaults-198M 72377.00 ( 0.00%) 39517.00 ( 45.40%) > Ops majorfaults-430M 71822.00 ( 0.00%) 38895.00 ( 45.85%) > Ops majorfaults-661M 70009.00 ( 0.00%) 39625.00 ( 43.40%) > Ops majorfaults-893M 74988.00 ( 0.00%) 38073.00 ( 49.23%) > Ops majorfaults-1125M 72458.00 ( 0.00%) 38206.00 ( 47.27%) > Ops majorfaults-1356M 70549.00 ( 0.00%) 37430.00 ( 46.94%) So the minor fault rate improved and everything else got worse? I'm not sure how representative this is of real workloads, but it does look rather fatal for zswap. The differences are so large, I wonder if it's just some silly bug or config issue. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>