On Fri, Dec 20, 2013 at 06:36:33AM -0600, Stan Hoeppner wrote: > On 12/20/2013 4:26 AM, Kevin Richter wrote: > > 'top' while copying with stripe size of 2048 (the source disk is ntfs): > >> top - 10:48:24 up 1 day, 1:41, 2 users, load average: 5.66, 3.53, 2.17 > >> Tasks: 210 total, 2 running, 208 sleeping, 0 stopped, 0 zombie > >> Cpu(s): 0.1%us, 35.8%sy, 0.0%ni, 46.0%id, 17.9%wa, 0.0%hi, 0.2%si, 0.0%st > >> Mem: 32913992k total, 32709208k used, 204784k free, 10770344k buffers > >> Swap: 7812496k total, 0k used, 7812496k free, 20866844k cached > >> > >> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > >> 19524 root 20 0 0 0 0 R 93 0.0 4:00.12 kworker/3:1 > >> 23744 root 20 0 0 0 0 S 55 0.0 0:50.84 kworker/0:1 > >> 23738 root 20 0 0 0 0 S 29 0.0 0:56.94 kworker/4:0 > >> 3893 root 20 0 0 0 0 S 28 0.0 36:47.50 md2_raid6 > >> 4551 root 20 0 22060 3328 720 D 25 0.0 20:21.61 mount.ntfs > >> 23273 root 20 0 0 0 0 S 22 0.0 1:54.86 kworker/7:2 > >> 23734 root 20 0 21752 1280 1040 D 21 0.0 0:49.84 cp > >> 84 root 20 0 0 0 0 S 7 0.0 8:19.34 kswapd1 > >> 83 root 20 0 0 0 0 S 6 0.0 11:55.81 kswapd0 > >> 23745 root 20 0 0 0 0 S 2 0.0 0:33.60 kworker/1:2 > >> 21598 root 20 0 0 0 0 D 1 0.0 0:11.33 kworker/u17:1 > > Hmm, what's kworker/3:1? That's not a crypto thread eating 93% of a > SandyBridge core at only ~180 MB/s throughput is it? Kworkers are an anonymous kernel worker threads that do work that has been pushed to a workqueue. kworker/3:1 is the 2nd worker thread on CPU 3 (3:0 is the first). The kworker is a thread pool that grows and shrinks according to demand. As the naming suggests, kworker threads are per-CPU, and there can be hundreds of them per CPU is there is enough workqueue work blocks during execution of the work (e.g. on locks, waiting for IO, etc). If there is little blocking occurring, there might on ly be a couple of kworker threads that do all the work, and hence you see them consuming huge amounts of CPU on behalf of other systems... XFS uses workqueues for lots of things, so it's not unusual to see an IO or metadata heavy workload end up with this huge numbers of kworker threads doing work: <run parallel fsmark test> .... $ ps -ef |grep kworker |wc -l 91 $ Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
