Hi Dong-Jae, > So, I tested dm-ioband and bio-cgroup patches with another IO testing > tool, xdd ver6.5(http://www.ioperformance.com/), after your reply. > Xdd supports O_DIRECT mode and time limit options. > I think, personally, it is proper tool for testing of IO controllers > in Linux Container ML. Xdd is really useful for me. Thanks for letting me know. > And I found some strange points in test results. In fact, it will be > not strange for other persons^^ > > 1. dm-ioband can control IO bandwidth well in O_DIRECT mode(read and > write), I think the result is very reasonable. but it can't control it > in Buffered mode when I checked just only output of xdd. I think > bio-cgroup patches is for solving the problems, is it right? If so, > how can I check or confirm the role of bio-cgroup patches? > > 2. As showed in test results, the IO performance in Buffered IO mode > is very low compared with it in O_DIRECT mode. In my opinion, the > reverse case is more natural in real life. > Can you give me a answer about it? Your results show all xdd programs belong to the same cgroup, could you explain me in detail about your test procedure? To know how many I/Os are actually issued to a physical device in buffered mode within a measurement period, you should check the /sys/block/<dev>/stat file just before starting a test program and just after the end of the test program. The contents of the stat file is described in the following document: kernel/Documentation/block/stat.txt > 3. Compared with physical bandwidth(when it is checked with one > process and without dm-ioband device), the sum of the bandwidth by > dm-ioband has very considerable gap with the physical bandwidth. I > wonder the reason. Is it overhead of dm-ioband or bio-cgroup patches? > or Are there any another reasons? The followings are the results on my PC with SATA disk, and there is no big difference between with and without dm-ioband. Please try the same thing if you have time. without dm-ioband ================= # xdd.linux -op write -queuedepth 16 -targets 1 /dev/sdb1 \ -reqsize 8 -numreqs 128000 -verbose -timelimit 30 -dio -randomize T Q Bytes Ops Time Rate IOPS Latency %CPU OP_Type ReqSize 0 16 140001280 17090 30.121 4.648 567.38 0.0018 0.01 write 8192 with dm-ioband ============== * cgroup1 (weight 10) # cat /cgroup/1/bio.id 1 # echo $$ > /cgroup/1/tasks # xdd.linux -op write -queuedepth 16 -targets 1 /dev/mapper/ioband1 -reqsize 8 -numreqs 128000 -verbose -timelimit 30 -dio -randomize T Q Bytes Ops Time Rate IOPS Latency %CPU OP_Type ReqSize 0 16 14393344 1757 30.430 0.473 57.74 0.0173 0.00 write 8192 * cgroup2 (weight 20) # cat /cgroup/2/bio.id 2 # echo $$ > /cgroup/2/tasks # xdd.linux -op write -queuedepth 16 -targets 1 /dev/mapper/ioband1 -reqsize 8 -numreqs 128000 -verbose -timelimit 30 -dio -randomize T Q Bytes Ops Time Rate IOPS Latency %CPU OP_Type ReqSize 0 16 44113920 5385 30.380 1.452 177.25 0.0056 0.00 write 8192 * cgroup3 (weight 60) # cat /cgroup/3/bio.id 3 # echo $$ > /cgroup/3/tasks # xdd.linux -op write -queuedepth 16 -targets 1 /dev/mapper/ioband1 -reqeize 8 -numreqs 128000 -verbose -timelimit 30 -dio -randomize T Q Bytes Ops Time Rate IOPS Latency %CPU OP_Type ReqSize 0 16 82485248 10069 30.256 2.726 332.79 0.0030 0.00 write 8192 Total ===== Bytes Ops Rate IOPS w/o dm-ioband 140001280 17090 4.648 567.38 w/ dm-ioband 140992512 17211 4.651 567.78 > > Could you give me the O_DIRECT patch? > > > Of course, if you want. But it is nothing > Tiobench tool is very simple and light source code, so I just add the > O_DIRECT option in tiotest.c of tiobench testing tool. > Anyway, after I make a patch file, I send it to you Thank you very much! Ryo Tsuruta -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
