pyocf: Introduce discard tests

Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>

tests/functional/tests/engine/test_discard.py

@@ -0,0 +1,123 @@
+#
+# Copyright(c) 2024 Huawei Technologies
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+import pytest
+
+from pyocf.types.cache import Cache, CacheMode, CacheLineSize
+from pyocf.types.data import Data
+from pyocf.types.core import Core
+from pyocf.types.io import IoDir, Sync
+from pyocf.types.volume import RamVolume, IoFlags, TraceDevice
+from pyocf.types.volume_core import CoreVolume
+from pyocf.utils import Size
+from math import ceil
+
+
+def test_discard_propagation(pyocf_ctx):
+    discards = {}
+
+    pyocf_ctx.register_volume_type(TraceDevice)
+
+    def trace_discard(vol, io, io_type):
+        nonlocal discards
+
+        if io_type == TraceDevice.IoType.Discard:
+            if vol.uuid not in discards:
+                discards[vol.uuid] = []
+            discards[vol.uuid].append((io.contents._addr, io.contents._bytes))
+
+        return True
+
+    cache_device = TraceDevice(RamVolume(Size.from_MiB(50)), trace_fcn=trace_discard)
+    core_device = TraceDevice(RamVolume(Size.from_MiB(100)), trace_fcn=trace_discard)
+
+    cache = Cache.start_on_device(cache_device)
+    core = Core.using_device(core_device)
+    queue = cache.get_default_queue()
+
+    cache.add_core(core)
+    volume = CoreVolume(core)
+    volume.open()
+
+    discards = {}
+
+    addr = Size.from_MiB(2).B
+    size = Size.from_MiB(1).B
+
+    io = volume.new_io(queue, addr, size, IoDir.WRITE, 0, 0)
+    data = Data(byte_count=0)
+    io.set_data(data, 0)
+
+    completion = Sync(io).submit_discard()
+    volume.close()
+
+    assert int(completion.results["err"]) == 0
+
+    assert core_device.uuid in discards
+
+    core_discards = discards[core_device.uuid]
+
+    assert len(core_discards) == 1
+    assert core_discards[0] == (addr, size)
+
+    cache.stop()
+
+
+@pytest.mark.parametrize("cls", CacheLineSize)
+@pytest.mark.parametrize("discard_addr", [63, 64, 65])
+@pytest.mark.parametrize("discard_size", [1, 127, 128, 129])
+def test_discard_invalidation(pyocf_ctx, cls, discard_addr, discard_size):
+    discard_addr = Size.from_KiB(discard_addr)
+    discard_size = Size.from_KiB(discard_size)
+
+    cache_device = RamVolume(Size.from_MiB(50))
+    core_device = RamVolume(Size.from_MiB(100))
+
+    cache = Cache.start_on_device(cache_device, cache_line_size=cls)
+    core = Core.using_device(core_device)
+    queue = cache.get_default_queue()
+
+    cache.add_core(core)
+    volume = CoreVolume(core)
+    volume.open()
+
+    data_size = Size.from_KiB(256)
+    pattern = b"\xff"
+
+    data = Data(data_size)
+    data.write(pattern * int(data_size), data_size)
+    io = volume.new_io(queue, 0, data_size, IoDir.WRITE, 0, 0)
+    io.set_data(data, 0)
+    Sync(io).submit()
+
+    data = Data(byte_count=0)
+    io = volume.new_io(queue, discard_addr, discard_size, IoDir.WRITE, 0, 0)
+    io.set_data(data, 0)
+    Sync(io).submit_discard()
+
+    if discard_size < cls:
+        expect_occupancy = data_size
+    else:
+        begin = Size(ceil(int(discard_addr) / cls) * cls)
+        end = min(Size((int(discard_addr + discard_size) // cls) * cls), data_size)
+        expect_occupancy = data_size - (end - begin)
+
+    assert cache.get_stats()["conf"]["occupancy"] == expect_occupancy
+
+    data = Data(data_size)
+    io = volume.new_io(queue, 0, data_size, IoDir.READ, 0, 0)
+    io.set_data(data, 0)
+    Sync(io).submit()
+
+    size = int(discard_addr)
+    assert bytes(data.buffer[:size]) == pattern * size
+
+    offset = int(discard_addr + discard_size)
+    size = int(data_size) - offset
+    assert bytes(data.buffer[offset:]) == pattern * size
+
+    volume.close()
+
+    cache.stop()