Hi Ritesh, On 19/9/17 18:32, Ritesh Harjani wrote: > Hello, > > This patch series is based on the upstream discussion with Jan > & Joseph @ [1]. > It is based on top of Matthew's v3 ext4 iomap patch series [2] > > Patch-1: Adds the ext4_ilock/unlock APIs and also replaces all > inode_lock/unlock instances from fs/ext4/* > > For now I already accounted for trylock/lock issue symantics > (which was discussed here [3]) in the same patch, > since the this whole patch was around inode_lock/unlock API, > so I thought it will be best to address that issue in the same patch. > However, kindly let me know if otherwise. > > Patch-2: Commit msg of this patch describes in detail about > what it is doing. > In brief - we try to first take the shared lock (instead of exclusive > lock), unless it is a unaligned_io or extend_io. Then in > ext4_dio_write_checks(), if we start with shared lock, we see > if we can really continue with shared lock or not. If not, then > we release the shared lock then acquire exclusive lock > and restart ext4_dio_write_checks(). > > > Tested against few xfstests (with dioread_nolock mount option), > those ran fine (ext4 & generic). > > I tried testing performance numbers on my VM (since I could not get > hold of any real h/w based test device). I could test the fact > that earlier we were trying to do downgrade_write() lock, but with > this patch, that path is now avoided for fio test case > (as reported by Joseph in [4]). > But for the actual results, I am not sure if VM machine testing could > really give the reliable perf numbers which we want to take a look at. > Though I do observe some form of perf improvements, but I could not > get any reliable numbers (not even with the same list of with/without > patches with which Joseph posted his numbers [1]). > > > @Joseph, > Would it be possible for you to give your test case a run with this > patches? That will be really helpful. > > Branch for this is hosted at below tree. > > https://github.com/riteshharjani/linux/tree/ext4-ilock-RFC > I've tested your branch, the result is: mounting with dioread_nolock, it behaves the same like reverting parallel dio reads + dioread_nolock; while mounting without dioread_nolock, no improvement, or even worse. Please refer the test data below. fio -name=parallel_dio_reads_test -filename=/mnt/nvme0n1/testfile -direct=1 -iodepth=1 -thread -rw=randrw -ioengine=psync -bs=$bs -size=20G -numjobs=8 -runtime=600 -group_reporting w/ = with parallel dio reads w/o = reverting parallel dio reads w/o+ = reverting parallel dio reads + dioread_nolock ilock = ext4-ilock-RFC ilock+ = ext4-ilock-RFC + dioread_nolock bs=4k: -------------------------------------------------------------- | READ | WRITE | -------------------------------------------------------------- w/ | 30898KB/s,7724,555.00us | 30875KB/s,7718,479.70us | -------------------------------------------------------------- w/o | 117915KB/s,29478,248.18us | 117854KB/s,29463,21.91us | -------------------------------------------------------------- w/o+ | 123450KB/s,30862,245.77us | 123368KB/s,30841,12.14us | -------------------------------------------------------------- ilock | 29964KB/s,7491,326.70us | 29940KB/s,7485,740.62us | -------------------------------------------------------------- ilock+| 123685KB/s,30921,245.52us | 123601KB/s,30900,12.11us | -------------------------------------------------------------- bs=16k: -------------------------------------------------------------- | READ | WRITE | -------------------------------------------------------------- w/ | 58961KB/s,3685,835.28us | 58877KB/s,3679,1335.98us | -------------------------------------------------------------- w/o | 218409KB/s,13650,554.46us | 218257KB/s,13641,29.22us | -------------------------------------------------------------- w/o+ | 222477KB/s,13904,552.94us | 222322KB/s,13895,20.28us | -------------------------------------------------------------- ilock | 56039KB/s,3502,632.96us | 55943KB/s,3496,1652.72us | -------------------------------------------------------------- ilock+| 222747KB/s,13921,552.57us | 222592KB/s,13912,20.31us | -------------------------------------------------------------- bs=64k ---------------------------------------------------------------- | READ | WRITE | ---------------------------------------------------------------- w/ | 119396KB/s,1865,1759.38us | 119159KB/s,1861,2532.26us | ---------------------------------------------------------------- w/o | 422815KB/s,6606,1146.05us | 421619KB/s,6587,60.72us | --------------------------------------------,------------------- w/o+ | 427406KB/s,6678,1141.52us | 426197KB/s,6659,52.79us | ---------------------------------------------------------------- ilock | 105800KB/s,1653,1451.68us | 105721KB/s,1651,3388.64us | ---------------------------------------------------------------- ilock+| 427678KB/s,6682,1142.13us | 426468KB/s,6663,52.31us | ---------------------------------------------------------------- bs=512k ---------------------------------------------------------------- | READ | WRITE | ---------------------------------------------------------------- w/ | 392973KB/s,767,5046.35us | 393165KB/s,767,5359.86us | ---------------------------------------------------------------- w/o | 590266KB/s,1152,4312.01us | 590554KB/s,1153,2606.82us | ---------------------------------------------------------------- w/o+ | 618752KB/s,1208,4125.82us | 619054KB/s,1209,2487.90us | ---------------------------------------------------------------- ilock | 296239KB/s,578,4703.10us | 296384KB/s,578,9049.32us | ---------------------------------------------------------------- ilock+| 616636KB/s,1204,4143.38us | 616937KB/s,1204,2490.08us | ---------------------------------------------------------------- bs=1M ---------------------------------------------------------------- | READ | WRITE | ---------------------------------------------------------------- w/ | 487779KB/s,476,8058.55us | 485592KB/s,474,8630.51us | ---------------------------------------------------------------- w/o | 593927KB/s,580,7623.63us | 591265KB/s,577,6163.42us | ---------------------------------------------------------------- w/o+ | 615011KB/s,600,7399.93us | 612255KB/s,597,5936.61us | ---------------------------------------------------------------- ilock | 394762KB/s,385,7097.55us | 392993KB/s,383,13626.98us | ---------------------------------------------------------------- ilock+| 626183KB/s,611,7319.16us | 623377KB/s,608,5773.24us | ---------------------------------------------------------------- Thanks, Joseph
