Hi Yuyang, On Wed, Jun 17, 2015 at 11:11:01AM +0800, Yuyang Du wrote: > Hi, > > The sched_debug is informative, lets first give it some analysis. > > The workload is 12 CPU hogging tasks (always runnable) and 1 dbench > task doing fs ops (70% runnable) running at the same time. > > Actually, these 13 tasks are in a task group /autogroup-9617, which > has weight 1024. > > So the 13 tasks at most can contribute to an average of 79 (=1024/13) >
[snip] > So the problem is: > > 1) The tasks in the workload have too small weight (only 79), because > they share a task group. > > 2) Probably some "high" weight task even runnable a small time > contribute "big" to cfs_rq's load_avg. Thank you for your analysis. Some updates: I created a task group /g and set /g/cpu.shares to 13312 (1024 * 13), and then ran `stress --cpu 12` and `dbench 1` simultaneously in that group. The situation is much better, only one CPU is not fully loaded, and its utilization rate stays around 85%. Regards, Boqun
signature.asc
Description: PGP signature
