Hi, Setting IOPRIO doesn't seem to properly distribute I/O for my VEs. I checked the Cgroup blkio and confirmed the blkio.weight is set in scale with the IOPRIO of each VE conf.
I tested ex. setting blkio.throttle.write_bps_device and confirmed Cgroup blkio is properly working (setting it to 1024000 does limit the VE to about 1MB/sec). I also checked the processes are properly listed in the Cgroup tasks. However, blkio.weight really doesn't seems to be doing anyting. I'm using the latest stable 2.6.32-042stab068.8. To test the I/O performance from inside my VE, I run the following in two separate VE, one with an IOPRIO of 1 (blkio.weight of 365) and the other with an IOPRIO of 7 (blkio.weight of 640) : while [ 1 ]; do dd if=/dev/zero of=test bs=1M count=100 oflag=direct; done Both give about the same results. The same seems to apply with plain ionice. I get very similar I/O performances independently of the Best-Effort priority I set. However setting one process in the Idle class and the other in Best-Effort does make a difference. I double checked and I am using the CFQ scheduler. Also my VE private directory are on top of an LVM volume, not sure if that could have an impact. Thanks Simon
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