Hello, On Mon, Jul 18, 2016 at 09:35:12PM +0800, 张真 wrote: > Hello > My name is Zhen Zhang , me and Jiale Li recently test and analyze the cgroup > blkio functions. > We tested the buffered read a file using bio when the > blkio.throttle.read_iops_device is set 1000. > The fio result file displays the iops is 13720 larger than 1000 when > blocksize > is 4K in fio.
blk-throttle does allow bursts so the iops might go over the set limit for a short period. Over time, it shouldn't be over the set limit. > We set different blocksize in fio: > 4K, 8K , 16K, 32K, 64K, 128K, 256K, 512K, 1024K > > The iops in fio: > 13035, 7258, 3711, 1698, 907, 460, 228, 102, 54 Looks like you were hitting the natural bandwidth limit of the device. > When bs is less than 64K, the iops is larger than 1000, when bs is larger than > 64K, the iops is less than 1000. > We tested it on ubuntu 16.04 with kernel 4.4.0 > > Dose this a problem of blkio iops throttle? I don't know how the test was run but consistently going over the set limit isn't the expected behavior. Thanks. -- tejun
