Re: [PATCH v5] scripts/simplebench: compare write request performance

[Vladimir Sementsov-Ogievskiy]

13.07.2020 20:22, Andrey Shinkevich wrote:
> The script 'bench_write_req.py' allows comparing performances of write
> request for two qemu-img binary files.
> An example with (qemu-img binary 1) and without (qemu-img binary 2) the
> applied patch "qcow2: skip writing zero buffers to empty COW areas"
> (git commit ID: c8bb23cbdbe32f5) has the following results:
>
> SSD:
> ----------------  -------------------  -------------------
>                    <qemu-img binary 1>  <qemu-img binary 2>
> <cluster front>   0.10 +- 0.00         8.16 +- 0.65
> <cluster middle>  0.10 +- 0.00         7.37 +- 1.10
> <cross cluster>   7.40 +- 1.08         21.97 +- 4.19
> <cluster 64K>     2.14 +- 0.94         8.48 +- 1.66
> ----------------  -------------------  -------------------
> HDD:
> ----------------  -------------------  -------------------
>                    <qemu-img binary 1>  <qemu-img binary 2>
> <cluster front>   2.30 +- 0.01         6.19 +- 0.06
> <cluster middle>  2.20 +- 0.09         6.20 +- 0.06
> <cross cluster>   8.32 +- 0.16         8.26 +- 0.14
> <cluster 64K>     8.20 +- 0.05         6.26 +- 0.10
> ----------------  -------------------  -------------------
>
> Suggested-by: Denis V. Lunev <den@openvz.org>
> Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
> v5:
>    01: 'cluster_size' made variable.
>    02: <simple case> deleted as duplicated.
>    03: A case with cluster size 64K was added.
>    04: The comments amended as Vladimir suggested.
>    05: Superfluous variables removed.
>    06: 'finally' block removed from function bench_write_req()
>    07: The names of test cases changed.
>    08: The 'block_size' of <cross cluster> set to the cluster size.
>
>   scripts/simplebench/bench_write_req.py | 170 +++++++++++++++++++++++++++++++++
>   1 file changed, 170 insertions(+)
>   create mode 100755 scripts/simplebench/bench_write_req.py
>
> diff --git a/scripts/simplebench/bench_write_req.py 
> b/scripts/simplebench/bench_write_req.py
> new file mode 100755
> index 0000000..7665c4b
> --- /dev/null
> +++ b/scripts/simplebench/bench_write_req.py
> @@ -0,0 +1,170 @@
> +#!/usr/bin/env python3
> +#
> +# Test to compare performance of write requests for two qemu-img binary files.
> +#
> +# The idea of the test comes from intention to check the benefit of c8bb23cbdbe
> +# "qcow2: skip writing zero buffers to empty COW areas".
> +#
> +# Copyright (c) 2020 Virtuozzo International GmbH.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 2 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +#
> +
> +

[..]

> +    # Test-cases are "rows" in benchmark resulting table, 'id' is a caption
> +    # for the row, other fields are handled by bench_func.
> +    test_cases = [
> +        {
> +            'id': '<cluster front>',
> +            'block_size': 4096,
> +            'block_offset': 0,
> +            'cluster_size': 1048576
> +        },
> +        {
> +            'id': '<cluster middle>',
> +            'block_size': 4096,
> +            'block_offset': 524288,
> +            'cluster_size': 1048576
> +        },
> +        {
> +            'id': '<cross cluster>',
> +            'block_size': 1048576,
> +            'block_offset': 4096,
> +            'cluster_size': 1048576
> +        },
> +        {
> +            'id': '<cluster 64K>',
> +            'block_size': 4096,
> +            'block_offset': 0,
> +            'cluster_size': 65536
> +        },
> +   ]

wrong indent (s/   /    /). with it fixed:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

> +
> +    # Test-envs are "columns" in benchmark resulting table, 'id is a caption
> +    # for the column, other fields are handled by bench_func.
> +    # Set the paths below to desired values
> +    test_envs = [
> +        {
> +            'id': '<qemu-img binary 1>',
> +            'qemu_img': f'{sys.argv[1]}',
> +            'image_name': f'{sys.argv[3]}'
> +        },
> +        {
> +            'id': '<qemu-img binary 2>',
> +            'qemu_img': f'{sys.argv[2]}',
> +            'image_name': f'{sys.argv[3]}'
> +        },
> +    ]
> +
> +    result = simplebench.bench(bench_func, test_envs, test_cases, count=3,
> +                               initial_run=False)
> +    print(simplebench.ascii(result))


--
Best regards,
Vladimir