Re: [PATCH blktests 2/2] block/011: Perform PCI reset while doing IO

[Omar Sandoval <osandov@osandov.com>]

On Mon, Jun 26, 2017 at 08:25:36AM -0600, Jens Axboe wrote:
> On 06/26/2017 08:06 AM, Johannes Thumshirn wrote:
> > On Fri, Jun 23, 2017 at 09:36:14AM -0600, Jens Axboe wrote:
> >> On 06/23/2017 08:29 AM, Johannes Thumshirn wrote:
> >>> From: Omar Sandoval <osandov@fb.com>
> >>>
> >>> This test-case performs I/O with fio while doing PCI disable/enable
> >>> cycles.
> >>>
> >>> In the results we don't care for I/O errors but for hiccups in dmesg only.
> >>
> >> Let's get this in, that would be a very useful test. A few comments -
> >> not necessarily on this patch in particular, but for future cleanups
> >> and improvements.
> >>
> >>> +	if _test_dev_is_rotational; then
> >>> +		size="32m"
> >>> +	else
> >>> +		size="1g"
> >>> +	fi
> >>
> >> I introduced this idea in one of my previous patches. I wonder if we
> >> should turn that into a helper. Pass in the dev, get returned a
> >> suitable fio size, instead of hard coding this in each job that
> >> needs it.

What I wanted to have here eventually is a helper that you can run when
you just want arbitrary I/O. Haven't gotten around to it.

> > 
> > Sure.
> > 
> >>
> >>> +	# start fio job
> >>> +	_run_fio --bs=4k --rw=randread --norandommap \
> >>> +		--name=reads --filename="$TEST_DEV" --size="$size" \
> >>> +		--numjobs=8 --direct=1 2>/dev/null &
> >>
> >> I don't believe we check for fio errors right now, but we probably
> >> should in the future. So I think you'd want to add something ala:
> >>
> >> --ignore_error=EIO,ENXIO,ENODEV
> >>
> >> to your options to make it explicit that you don't care about IO
> >> errors for this test.

Yup, we redirect fio errors to /dev/null everywhere, we should fix that.

> > Oh nice, didn't know about the option. Btw as we're currently all have
> > arbitrary values for the numjobs parameter, how about a wrapper over getconf
> > _NPROCESSORS_ONLN?
> 
> Yes that's a good idea, then we can at least size the jobs based on
> how many cores we have.

We can just use nproc for this.