tests: lib: lockfree: Fix MPSC test consumer node return logic #97740
+28
−1
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The MPSC test consumer was incorrectly handling node returns to producer free queues. It called spsc_acquire() without checking the return value, then unconditionally called spsc_produce(). When the SPSC free queue was full, spsc_acquire() would return NULL and not increment the acquire counter, causing spsc_produce() to silently do nothing (it only produces if acquire > 0). This resulted in lost nodes. At least on QEMU, a 4-CPU configuration is needed for this bug to manifest. Producers put all nodes in flight simultaneously with the single consumer unable to keep up, causing frequent SPSC queue full conditions. The Fix: Loop on spsc_acquire() until it succeeds before calling spsc_produce(). This ensures nodes are always successfully returned to producer queues. Added board overlay for qemu_cortex_a53/smp to enable 4-CPU testing, which reproduces the issue and validates the fix. Signed-off-by: Nicolas Pitre <[email protected]>
|
zephyrbot
added
the
area: Tests
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The MPSC test consumer was incorrectly handling node returns to
producer free queues. It called spsc_acquire() without checking the
return value, then unconditionally called spsc_produce(). When the
SPSC free queue was full, spsc_acquire() would return NULL and not
increment the acquire counter, causing spsc_produce() to silently do
nothing (it only produces if acquire > 0). This resulted in lost nodes.
At least on QEMU, a 4-CPU configuration is needed for this bug to manifest.
Producers put all nodes in flight simultaneously with the single consumer
unable to keep up, causing frequent SPSC queue full conditions.
The Fix: Loop on spsc_acquire() until it succeeds before calling
spsc_produce(). This ensures nodes are always successfully returned to
producer queues.
Added board overlay for qemu_cortex_a53/smp to enable 4-CPU testing,
which reproduces the issue and validates the fix.