Re: dumping queue state

Bart Van Assche
2017-12-20T16:14:48Z

On Wed, 2017-12-20 at 09:53 -0600, Steve Wise wrote:
> I have a need to provide tools for customers to gather runtime state for an
> rdma device. Say, when an application is stuck waiting for some completion
> or other rdma event. This includes hw/fw state of course, and equally as
> important, rdma object sw state. Is debugfs the correct way to export this
> sw state? The data is quite large potentially; each QP, its structures, the
> dma queue memory, etc. Ditto for CQs. Also MR state, etc etc. It seems
> that would be overloading debugfs to me. Currently the hw/fw state is being
> gathered via ethtool dump commands (--get-dump, --register-dump,
> --eeprom-dump). I am considering using the ethtool --get-dump method for
> the low level driver to also include dumping the rdma queue state for the
> device. Is that a reasonable approach?
>
> Any thoughts/suggestions?

Hello Steve,

I'm not sure what the best solution is for RDMA queues. But if you want you can
have a look at block/blk-mq-debugfs.c. That code has been added recently and has
been very valuable for debugging block layer / SCSI queue lockups.

Bart.