> Il giorno 20 ago 2019, alle ore 12:48, Paolo Valente <paolo.valente@xxxxxxxxxx> ha scritto: > > > >> Il giorno 14 giu 2019, alle ore 19:56, Tejun Heo <tj@xxxxxxxxxx> ha scritto: >> >> On Thu, Jun 13, 2019 at 06:56:10PM -0700, Tejun Heo wrote: >> ... >>> The patchset is also available in the following git branch. >>> >>> git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-iow >> >> Updated patchset available in the following branch. Just build fixes >> and cosmetic changes for now. >> >> git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-iow-v2 >> > > Hi Tejun, > I'm running the kernel in your tree above, in an Ubuntu 18.04. > > After unmounting the v1 blkio controller that gets mounted at startup > I have created v2 root as follows > > $ mount -t cgroup2 none /cgroup > > Then I have: > $ ls /cgroup > cgroup.controllers cgroup.max.descendants cgroup.stat cgroup.threads io.weight.cost_model system.slice > cgroup.max.depth cgroup.procs cgroup.subtree_control init.scope io.weight.qos user.slice > > But the following command gives no output: > $ cat /cgroup/io.weight.qos > > And, above all, > $ echo 1 > /cgroup/io.weight.qos > bash: echo: write error: Invalid argument > > No complain in the kernel log. > > What am I doing wrong? How can I make the controller work? > I made it, sorry for my usual silly questions (for some reason, I thought the controller could be enabled globally by just passing a 1). The problem now is that the controller doesn't seem to work. I've emulated 16 clients doing I/O on a SATA SSD. One client, the target, does random reads, while the remaining 15 clients, the interferers, do sequential reads. Each client is encapsulated in a separate group, but whatever weight is assigned to the target group, the latter gets the same, extremely low bandwidth. I have tried with even the maximum weight ratio, i.e., 1000 for the target and only 1 for each interferer. Here are the results, compared with BFQ (bandwidth in MB/s): io.weight BFQ 0.2 3.7 I ran this test with the script S/bandwidth-latency/bandwidth-latency.sh of the S benchmark suite [1], invoked as follows: sudo ./bandwidth-latency.sh -t randread -s none -b weight -n 15 -w 1000 -W 1 The above command simply creates groups, assigns weights as follows echo 1 > /cgroup/InterfererGroup0/io.weight echo 1 > /cgroup/InterfererGroup1/io.weight ... echo 1 > /cgroup/InterfererGroup14/io.weight echo 1000 > /cgroup/interfered/io.weight and makes one fio instance generate I/O for each group. The bandwidth reported above is that reported by the fio instance emulating the target client. Am I missing something? Thanks, Paolo [1] https://github.com/Algodev-github/S > Thanks, > Paolo > >> Thanks. >> >> -- >> tejun >
