On 07/23/2013 05:56 PM, Tejun Heo wrote: >> On 06/27/2013 07:17 PM, Holger Brunck wrote: >> >> On a single ARM CPU (kirkwood) I see the same confusing results similar to the >> results of the above powerpc example: >> >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND >> 232 root 20 0 1924 492 420 R 99.9 0.4 0:29.15 dd >> 234 root 20 0 1924 492 420 R 0.3 0.4 0:00.13 dd >> >> I doublechecked this on my local host x86_64 multicore and here it works fine >> even if I force both dd processes to run on the same CPU: >> >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND >> 32046 root 20 0 102m 516 432 R 49.4 0.0 0:32.49 dd >> 32049 root 20 0 102m 516 432 R 49.4 0.0 0:13.39 dd >> >> So either it's a problem for single CPUs or it's not allowed at all and works >> only by chance. > > Can you please boot with maxcpus=1 and see whether that makes the > issue reproducible on x86? > I retested this with maxcpus=0 to disable SMP completely and it works, both processes share 50% of the CPU. But I have to admit that I currently have only a 3.4 setup for my x86_64 PC. My setup for an arm kirkwood board and a board with a powerpc 8247 runs latest 3.10 kernel where I see the problem that one process is starving. But the problem was already present in a 3.0.x kernel. So it seems to be a architecture dependent problem. Regards Holger -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
