Modify buffer overflow logic for System.Buffers.ArrayPool.Tests.ArrayPoolUnitTests.ReturnBufferWhenFullFiresDroppedDiagnosticEvent #112849
Conversation
This file contains 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
…ferWhenFullFiresDroppedDiagnosticEvent' fails on systems with cpu cores >= 32.
The test begins by renting from a SharedArrayPool 1 byte using the 'Rent' function for 1000 iterations and returning the bytes rented using the 'Return' function back to the SharedArrayPool. The test expects
that returning a large number of bytes(in this case 1000) overflows the SharedArrayPool hence dropping it. The test case fails in machines that have cpu cores greater than 32 because the capacity of the SharedArrayPool is dependent on the number
of processors. It happens to be 'number of processors' * 32. Clearly the size of the SharedArrayPool in case of 32 cpu cores would be 32*32=1024 which is greater than 1000 and hence doesn't overflow the
SharedArrayPool and hence failing test case. We actualy need ('number of processors' * 32 + 2) iterations because ('number of processors' * 32 + 1) bytes would be required to overflow the buffer and the ith
iteration actually caches the byte to TLA and push the (i-1)th byte to the pool. Hence ('number of processors + 32' + 1)th byte would be returned on the ('number of processors + 32' + 2)nd iterations.
dotnet-issue-labeler
bot
added
the
needs-area-label
dotnet-policy-service
bot
added
the
community-contribution
huoyaoyuan
added
area-System.Buffers
and removed
needs-area-label
|
Tagging subscribers to this area: @dotnet/area-system-buffers |
|
@stephentoub Can you review this please. |
This was referenced Feb 26, 2025
Open
|
background failures seem to be unrelated. |
Yes. But what is the urgency? |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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 test 'System.Buffers.ArrayPool.Tests.ArrayPoolUnitTests.ReturnBufferWhenFullFiresDroppedDiagnosticEvent' fails on systems with cpu cores >= 32.
The test begins by renting from a SharedArrayPool 1 byte using the 'Rent' function for 1000 iterations and returning the bytes rented using the 'Return' function back to the SharedArrayPool.
The test expects that returning a large number of bytes(in this case 1000) overflows the SharedArrayPool hence dropping it. The test case fails in machines that have cpu cores greater than 32 because the capacity of the SharedArrayPool is dependent on the number of processors. It happens to be 'number of processors' * 32.
The size of the SharedArrayPool in case of 32 cpu cores would be 32*32=1024 which is greater than 1000 and hence doesn't overflow the SharedArrayPool and hence failing test case. We actualy need ('number of processors' * 32 + 2) iterations because ('number of processors' * 32 + 1) bytes would be required to overflow the buffer and the ith iteration actually caches the byte to TLA and push the (i-1)th byte to the pool. Hence ('number of processors + 32' + 1)th byte would be returned on the ('number of processors + 32' + 2)nd iteration. see link