def test_dask_optimized_slicing(delayed_dask_stack, monkeypatch):
"""Test that dask_configure reduces compute with dask stacks."""
# add dask stack to the viewer, making sure to pass multiscale and clims
v = viewer.ViewerModel()
dask_stack = delayed_dask_stack['stack']
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert delayed_dask_stack['calls'] == 1 # the first stack will be loaded
# changing the Z plane should never incur calls
# since the stack has already been loaded (& it is chunked as a 3D array)
for i in range(3):
v.dims.set_point(1, i)
assert delayed_dask_stack['calls'] == 1 # still just the first call
# changing the timepoint will, of course, incur some compute calls
v.dims.set_point(0, 1)
assert delayed_dask_stack['calls'] == 2
v.dims.set_point(0, 2)
assert delayed_dask_stack['calls'] == 3
# but going back to previous timepoints should not, since they are cached
v.dims.set_point(0, 1)
v.dims.set_point(0, 0)
assert delayed_dask_stack['calls'] == 3
v.dims.set_point(0, 3)
assert delayed_dask_stack['calls'] == 4
def test_prevent_dask_cache(delayed_dask_stack):
"""Test that pre-emptively setting cache to zero keeps it off"""
# the del is not required, it just shows that prior state of the cache
# does not matter... calling resize_dask_cache(0) will permanently disable
del utils.dask_cache
utils.resize_dask_cache(0)
v = viewer.ViewerModel()
dask_stack = delayed_dask_stack['stack']
# adding a new stack will not increase the cache size
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes == 0
# and the cache will not be populated
for i in range(3):
v.dims.set_point(0, i)
assert len(utils.dask_cache.cache.heap.heap) == 0
def test_dask_cache_resizing(delayed_dask_stack):
"""Test that we can spin up, resize, and spin down the cache."""
# add dask stack to the viewer, making sure to pass multiscale and clims
utils.dask_cache = None
v = viewer.ViewerModel()
dask_stack = delayed_dask_stack['stack']
# adding a new stack should spin up a cache
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes > 0
# make sure the cache actually has been populated
assert len(utils.dask_cache.cache.heap.heap) > 0
# we can resize that cache back to 0 bytes
utils.resize_dask_cache(0)
assert utils.dask_cache.cache.available_bytes == 0
# adding a 2nd stack should not adjust the cache size once created
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes == 0
# and the cache will remain empty regardless of what we do
for i in range(3):
v.dims.set_point(1, i)
assert len(utils.dask_cache.cache.heap.heap) == 0
# but we can always spin it up again
utils.resize_dask_cache(1e4)
assert utils.dask_cache.cache.available_bytes == 1e4
# and adding a new image doesn't change the size
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes == 1e4
# but the cache heap is getting populated again
for i in range(3):
v.dims.set_point(0, i)
assert len(utils.dask_cache.cache.heap.heap) > 0
# however, if the dask_cache attribute is deleted entirely (or set to None)
# we will have no memory of it ever having been created.
# and adding a new stack will spin up a cache
del utils.dask_cache
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes > 0
def test_dask_unoptimized_slicing(delayed_dask_stack, monkeypatch):
"""Prove that the dask_configure function works with a counterexample."""
# make sure we are not caching for this test, which also tests that we
# can turn off caching
utils.resize_dask_cache(0)
assert utils.dask_cache.cache.available_bytes == 0
# mock the dask_configure function to return a no-op.
def mock_dask_config(data):
@contextmanager
def dask_optimized_slicing(*args, **kwds):
yield {}
return dask_optimized_slicing
monkeypatch.setattr(layers.base.base, 'configure_dask', mock_dask_config)
# add dask stack to viewer.
v = viewer.ViewerModel()
dask_stack = delayed_dask_stack['stack']
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert delayed_dask_stack['calls'] == 1
# without optimized dask slicing, we get a new call to the get_array func
# (which "re-reads" the full z stack) EVERY time we change the Z plane
# even though we've already read this full timepoint.
for i in range(3):
v.dims.set_point(1, i)
assert delayed_dask_stack['calls'] == 1 + i # 😞
# of course we still incur calls when moving to a new timepoint...
v.dims.set_point(0, 1)
v.dims.set_point(0, 2)
assert delayed_dask_stack['calls'] == 5
# without the cache we ALSO incur calls when returning to previously loaded
# timepoints ðŸ˜
v.dims.set_point(0, 1)
v.dims.set_point(0, 0)
v.dims.set_point(0, 3)
# all told, we have ~2x as many calls as the optimized version above.
# (should be exactly 8 calls, but for some reason, sometimes less on CI)
assert delayed_dask_stack['calls'] >= 7
def test_dask_cache_resizing(delayed_dask_stack):
"""Test that we can spin up, resize, and spin down the cache."""
# make sure we have a cache
# big enough for 10+ (10, 10, 10) "timepoints"
utils.resize_dask_cache(100000)
# add dask stack to the viewer, making sure to pass multiscale and clims
v = viewer.ViewerModel()
dask_stack = delayed_dask_stack['stack']
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes > 0
# make sure the cache actually has been populated
assert len(utils.dask_cache.cache.heap.heap) > 0
# we can resize that cache back to 0 bytes
utils.resize_dask_cache(0)
assert utils.dask_cache.cache.available_bytes == 0
# adding a 2nd stack should not adjust the cache size once created
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes == 0
# and the cache will remain empty regardless of what we do
for i in range(3):
v.dims.set_point(1, i)
assert len(utils.dask_cache.cache.heap.heap) == 0
# but we can always spin it up again
utils.resize_dask_cache(1e4)
assert utils.dask_cache.cache.available_bytes == 1e4
# and adding a new image doesn't change the size
v.add_image(dask_stack, multiscale=False, contrast_limits=(0, 1))
assert utils.dask_cache.cache.available_bytes == 1e4
# but the cache heap is getting populated again
for i in range(3):
v.dims.set_point(0, i)
assert len(utils.dask_cache.cache.heap.heap) > 0