Re: [PATCH 1/3] generic: fsstress with cpu offlining

[Eryu Guan <guan@eryu.me>]

On Tue, Aug 31, 2021 at 05:11:50PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Exercise filesystem operations when we're taking CPUs online and offline
> throughout the test.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  tests/generic/726     |   69 +++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/726.out |    2 +
>  2 files changed, 71 insertions(+)
>  create mode 100755 tests/generic/726
>  create mode 100644 tests/generic/726.out
> 
> 
> diff --git a/tests/generic/726 b/tests/generic/726
> new file mode 100755
> index 00000000..cb709795
> --- /dev/null
> +++ b/tests/generic/726
> @@ -0,0 +1,69 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2021 Oracle, Inc.  All Rights Reserved.
> +#
> +# FS QA Test No. 726
> +#
> +# Run an all-writes fsstress run with multiple threads while exercising CPU
> +# hotplugging to shake out bugs in the write path.
> +#
> +. ./common/preamble
> +_begin_fstest auto rw stress
> +
> +# Override the default cleanup function.
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.*
> +	$KILLALL_PROG -9 fsstress > /dev/null 2>&1
> +	wait	# for exercise_cpu_hotplug subprocess
> +	for i in "$sysfs_cpu_dir/"cpu*/online; do
> +		echo 1 > "$i" 2>/dev/null
> +	done
> +}
> +
> +exercise_cpu_hotplug()
> +{
> +	while [ -e $sentinel_file ]; do
> +		local idx=$(( RANDOM % nr_hotplug_cpus ))
> +		local cpu="${hotplug_cpus[idx]}"
> +		local action=$(( RANDOM % 2 ))
> +
> +		echo "$action" > "$sysfs_cpu_dir/cpu$cpu/online" 2>/dev/null
> +		sleep 0.5
> +	done
> +}
> +
> +_supported_fs generic
> +
> +sysfs_cpu_dir="/sys/devices/system/cpu"
> +
> +# Figure out which CPU(s) support hotplug.
> +nrcpus=$(getconf _NPROCESSORS_CONF)
> +hotplug_cpus=()
> +for ((i = 0; i < nrcpus; i++ )); do
> +	test -e "$sysfs_cpu_dir/cpu$i/online" && hotplug_cpus+=("$i")
> +done
> +nr_hotplug_cpus="${#hotplug_cpus[@]}"
> +test "$nr_hotplug_cpus" -gt 0 || _notrun "CPU hotplugging not supported"
> +
> +_require_scratch
> +_require_command "$KILLALL_PROG" "killall"
> +
> +echo "Silence is golden."
> +
> +_scratch_mkfs > $seqres.full 2>&1
> +_scratch_mount >> $seqres.full 2>&1

I think we could just run fsstress against a dir in $TEST_DIR?

> +
> +sentinel_file=$tmp.hotplug
> +touch $sentinel_file
> +exercise_cpu_hotplug &
> +
> +nr_cpus=$((LOAD_FACTOR * nr_hotplug_cpus))

We'd better to cap nr_cpu just in case we're testing on a system with
1024 cpus and taking very long time for fsstress to finish.

Thanks,
Eryu

> +nr_ops=$((25000 * TIME_FACTOR))
> +$FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n $nr_ops -p $nr_cpus >> $seqres.full
> +rm -f $sentinel_file
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/726.out b/tests/generic/726.out
> new file mode 100644
> index 00000000..6839f8ce
> --- /dev/null
> +++ b/tests/generic/726.out
> @@ -0,0 +1,2 @@
> +QA output created by 726
> +Silence is golden.
>