pyocf: settle cache before testing occupancy

The next commit will move occupancy accounting to backfill which makes
testing statistics value even more time dependent. Settling cache before
cache.get_stats() prevents this error-inducing race conditions

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>

tests/functional/tests/eviction/test_eviction.py

@@ -1,10 +1,11 @@
 #
 # Copyright(c) 2019-2022 Intel Corporation
-# Copyright(c) 2024 Huawei Technologies
+# Copyright(c) 2024-2025 Huawei Technologies
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
 import logging
+import time
 from math import ceil, isclose
 from ctypes import c_int
 
@@ -45,6 +46,8 @@ def test_eviction_two_cores(pyocf_ctx, mode: CacheMode, cls: CacheLineSize):
     send_io(vol1, test_data)
     send_io(vol2, test_data)
 
+    cache.settle()
+
     stats1 = core1.get_stats()
     stats2 = core2.get_stats()
     # IO to the second core should evict all the data from the first core
@@ -285,6 +288,7 @@ def test_eviction_freelist(pyocf_ctx, cls: CacheLineSize, cache_mode: CacheMode,
         for j in range(cache_lines_written):
             addr = (cache_lines_written * i + j) * data.size
             send_io(vol, data, addr, ioclass, io_dir)
+            cache.settle()
         assert (
             get_ioclass_occupancy(cache, ioclass) == expected_occpancy_4k
         ), f"Doesn't match for ioclass {ioclass}"
@@ -298,6 +302,9 @@ def test_eviction_freelist(pyocf_ctx, cls: CacheLineSize, cache_mode: CacheMode,
         addr += data.size
         send_io(vol, data, addr, high_prio_ioclass, io_dir)
 
+    cache.settle()
+    time.sleep(1)
+
     assert cache.get_stats()["usage"]["occupancy"]["value"] == cache_size_4k
 
     for ioclass in low_prio_ioclasses:

tests/functional/tests/management/test_start_stop.py

@@ -1,6 +1,6 @@
 #
 # Copyright(c) 2019-2022 Intel Corporation
-# Copyright(c) 2024 Huawei Technologies
+# Copyright(c) 2024-2025 Huawei Technologies
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -212,7 +212,9 @@ def test_stop(pyocf_ctx, mode: CacheMode, cls: CacheLineSize, with_flush: bool):
 
     cls_no = 10
 
-    run_io_and_cache_data_if_possible(front_vol, mode, cls, cls_no)
+    run_io_and_cache_data_if_possible(cache, front_vol, mode, cls, cls_no)
+
+    cache.settle()
 
     stats = cache.get_stats()
     assert int(stats["conf"]["dirty"]) == (
@@ -494,7 +496,7 @@ def test_start_stop_noqueue(pyocf_ctx):
     assert not c.results["error"], "Failed to stop cache: {}".format(c.results["error"])
 
 
-def run_io_and_cache_data_if_possible(vol, mode, cls, cls_no):
+def run_io_and_cache_data_if_possible(cache, vol, mode, cls, cls_no):
     queue = vol.parent.get_default_queue()
 
     test_data = Data(cls_no * cls)
@@ -508,6 +510,8 @@ def run_io_and_cache_data_if_possible(vol, mode, cls, cls_no):
         logger.info("[STAGE] Write to exported object")
         io_to_core(vol, queue, test_data, 0)
 
+    cache.settle()
+
     stats = vol.parent.cache.get_stats()
     assert stats["usage"]["occupancy"]["value"] == (
         (cls_no * cls / CacheLineSize.LINE_4KiB) if mode != CacheMode.PT else 0