[PATCH v3 3/4] scripts/simplebench: add example usage of simplebench

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

This example may be used as a template for custom benchmark.
It illustrates three things to prepare:
 - define bench_func
 - define test environments (columns)
 - define test cases (rows)
And final call of simplebench API.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 scripts/simplebench/bench-example.py | 80 ++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 scripts/simplebench/bench-example.py

diff --git a/scripts/simplebench/bench-example.py b/scripts/simplebench/bench-example.py
new file mode 100644
index 0000000000..c642a5b891
--- /dev/null
+++ b/scripts/simplebench/bench-example.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+#
+# Benchmark example
+#
+# Copyright (c) 2019 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/>.
+#
+
+import simplebench
+from bench_block_job import bench_block_copy, drv_file, drv_nbd
+
+
+def bench_func(env, case):
+    """ Handle one "cell" of benchmarking table. """
+    return bench_block_copy(env['qemu_binary'], env['cmd'],
+                            case['source'], case['target'])
+
+
+# You may set the following five variables to correct values, to turn this
+# example to real benchmark.
+ssd_source = '/path-to-raw-source-image-at-ssd'
+ssd_target = '/path-to-raw-target-image-at-ssd'
+hdd_target = '/path-to-raw-source-image-at-hdd'
+nbd_ip = 'nbd-ip-addr'
+nbd_port = 'nbd-port-number'
+
+# 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': 'ssd -> ssd',
+        'source': drv_file(ssd_source),
+        'target': drv_file(ssd_target)
+    },
+    {
+        'id': 'ssd -> hdd',
+        'source': drv_file(ssd_source),
+        'target': drv_file(hdd_target)
+    },
+    {
+        'id': 'ssd -> nbd',
+        'source': drv_file(ssd_source),
+        'target': drv_nbd(nbd_ip, nbd_port)
+    },
+]
+
+# Test-envs are "columns" in benchmark resulting table, 'id is a caption for
+# the column, other fields are handled by bench_func.
+test_envs = [
+    {
+        'id': 'backup-1',
+        'cmd': 'blockdev-backup',
+        'qemu_binary': '/path-to-qemu-binary-1'
+    },
+    {
+        'id': 'backup-2',
+        'cmd': 'blockdev-backup',
+        'qemu_binary': '/path-to-qemu-binary-2'
+    },
+    {
+        'id': 'mirror',
+        'cmd': 'blockdev-mirror',
+        'qemu_binary': '/path-to-qemu-binary-1'
+    }
+]
+
+result = simplebench.bench(bench_func, test_envs, test_cases, count=3)
+print(simplebench.ascii(result))
-- 
2.21.0