[Lustre-discuss] [zfs-discuss] ZFS/Lustre echo 0 >> max_cached_mb chewing 100% cpu

[Andrew Holway]

On 22 October 2013 16:21, Prakash Surya <surya1 at llnl.gov> wrote:
> This probably belongs on the Lustre mailing list.

I cross posted :)

> Regardless, I don't
> think you want to do that (do you?). It'll prevent any client side
> caching, and more importantly, I don't think it's a case that's been
> tested/optimized. What're you trying to acheive?

Sorry I was not clear, I didn't action this and I cant kill the
process. It seemed to start directly after running:

"FSTYPE=zfs /usr/lib64/lustre/tests/llmount.sh"

I have tried to kill it first with -2 upto -9 but the process will not budge.

Here is the top lines from perf top

37.39%  [osc]              [k] osc_set_info_async
 27.14%  [lov]              [k] lov_set_info_async
  4.13%  [kernel]           [k] kfree
  3.57%  [ptlrpc]           [k] ptlrpc_set_destroy
  3.14%  [kernel]           [k] mutex_unlock
  3.10%  [lustre]           [k] ll_wr_max_cached_mb
  3.00%  [kernel]           [k] mutex_lock
  2.82%  [ptlrpc]           [k] ptlrpc_prep_set
  2.52%  [kernel]           [k] __kmalloc

Thanks,

Andrew

>
> Also, just curious, where's the CPU time being spent? What process and/or
> kernel thread? What are the top entries listed when you run "perf top"?
>
> --
> Cheers, Prakash
>
> On Tue, Oct 22, 2013 at 12:53:44PM +0100, Andrew Holway wrote:
>> Hello,
>>
>> I have just setup a "toy" lustre setup using this guide here:
>> http://zfsonlinux.org/lustre and have this process chewing 100% cpu.
>>
>> sh -c echo 0 >> /proc/fs/lustre/llite/lustre-ffff88006b0c7c00/max_cached_mb
>>
>> Until I get something more beasty I am using my desktop machine with
>> KVM. Using standard Centos 6.4 with latest kernel. (2.6.32-358.23.2).
>> my machine has 2GB ram
>>
>> Any ideas?
>>
>> Thanks,
>>
>> Andrew
>>
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