Re: [PATCH v4 10/10] scsi: Implement blk_mq_ops.show_rq()

Bart Van Assche
2017-04-24T21:49:37Z

On Mon, 2017-04-24 at 17:35 -0400, Martin K. Petersen wrote:
> > Show the SCSI CDB, .eh_eflags and .result for pending SCSI commands
> > in /sys/kernel/debug/block/*/mq/*/dispatch and */rq_list.
>=20
> Why not use SCSI tracing if you are interested in these?

Hello Martin,

SCSI tracing has to be enabled before a test is started, produces a huge am=
ount
of data, and deriving state information from a huge trace is far from easy.=
The
information in debugfs provides an easy to read overview of the current sta=
te
without having to analyze megabytes of traces, without introducing any slow=
down
and without having to enable any tracing mechanism from beforehand.

Bart.=