Running the below testcase shows each process consuming 41-43% of it's respective cpu while per core idle numbers show 63-65%, a disparity of roughly 4-8%. Is this a bug, known behaviour, or consequence of the process being io bound?
1. run sudo taskset -c 0 netserver 2. run taskset -c 1 netperf -H localhost -l 3600 -t TCP_RR & (start netperf with priority on cpu1) 3. run top, press 1 for multiple CPUs to be separated The below output is the top output notice the cpu0 idle at 67% when the processes claim 42% usage a roughly 9% discrepancy. ------------------------------------------------ top - 19:27:38 up 4:08, 2 users, load average: 0.45, 0.19, 0.13 Tasks: 85 total, 2 running, 83 sleeping, 0 stopped, 0 zombie %Cpu0 : 0.8 us, 15.4 sy, 0.0 ni, 66.7 id, 0.0 wa, 0.0 hi, 17.1 si, 0.0 st %Cpu1 : 0.8 us, 17.3 sy, 0.0 ni, 63.1 id, 0.0 wa, 0.0 hi, 18.8 si, 0.0 st KiB Mem: 4049180 total, 252952 used, 3796228 free, 23108 buffers KiB Swap: 0 total, 0 used, 0 free, 132932 cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 6150 root 20 0 9756 700 536 R 42.6 0.0 0:48.90 netserver 6149 ubuntu 20 0 11848 1056 852 S 42.2 0.0 0:48.92 netperf ------------------------------------------------ The above testcase was run on 3.10-rc6. So is this a bug or can someone explain to me why this isn't a bug? The related ubuntu bug is https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1193073 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
