Re: [PATCH] blktests: test turning wbt on and off

[Omar Sandoval <osandov@osandov.com>]

On Wed, Dec 12, 2018 at 04:58:53PM -0500, Josef Bacik wrote:
> There have been a few issues with turning wbt on and off while IO is in
> flight, so add a test that just does some random rw IO and has a
> background thread that toggles wbt on and off.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  tests/block/027     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>  tests/block/027.out |  2 ++
>  2 files changed, 49 insertions(+)
>  create mode 100755 tests/block/027
>  create mode 100644 tests/block/027.out
> 
> diff --git a/tests/block/027 b/tests/block/027
> new file mode 100755
> index 000000000000..dce6431172a8
> --- /dev/null
> +++ b/tests/block/027
> @@ -0,0 +1,47 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-3.0+
> +# Copyright (C) 2018 Josef Bacik
> +#
> +# Turn wbt on and off in the background while writing to the disk to verify
> +# there's no races in the inflight counter manipulation
> +
> +. tests/block/rc
> +
> +DESCRIPTION="run a read workload and write workload together with wbt"
> +
> +requires() {
> +	_have_fio && _have_program jq

This test doesn't use jq.

> +}
> +
> +device_requires() {
> +	_test_dev_supports_wbt
> +}
> +
> +toggle_wbt() {
> +	while true
> +	do
> +		_test_dev_queue_set wbt_lat_usec 0
> +		sleep 1
> +		_test_dev_queue_set wbt_lat_usec 1
> +		sleep 1			
Trailing whitespace.   ^^^^^^^^^^^^^^^^^

> +	done
> +}
> +
> +test_device() {

Since this is entirely in the block layer, this test doesn't seem like
it needs a real device. Can it use null_blk instead? See block/006 for
an example.

> +	echo "Running ${TEST_NAME}"
> +
> +	local wbt_setting toggle_pid
> +	wbt_setting=$(_test_dev_queue_get wbt_lat_usec)
> +
> +	(toggle_wbt &)
> +	toggle_pid=$!
> +
> +	_run_fio --name randrw --numjobs=8 --runtime=30 --randseed=12345 \
> +		--ioengine=psync --readwrite=randrw --filename="$TEST_DEV"

If you leave off --runtime=30 here, _run_fio will automatically use the
configured TIMEOUT, and you can make this a TIMED test (i.e., set
TIMED=1 after DESCRIPTION=).

> +	kill $toggle_pid > /dev/null 2>&1
> +	wait
> +	_test_dev_queue_set wbt_lat_usec "$wbt_setting"
> +
> +	echo "Test complete"
> +}
> diff --git a/tests/block/027.out b/tests/block/027.out
> new file mode 100644
> index 000000000000..b03498fbc763
> --- /dev/null
> +++ b/tests/block/027.out
> @@ -0,0 +1,2 @@
> +Running block/027
> +Test complete
> -- 
> 2.14.3
>