Avoid a list/array allocation in Task.WhenAll(enumerable) #110536
Merged
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
When the incoming enumerable isn't a `Task[]` or `List<Task>`, we end up allocating either a `Task[]` or a `List<T>` (which then may incur one or more array allocations under the covers). We can avoid that by using a builder, either seeded with stack memory for
ghost
added
the
needs-area-label
teo-tsirpanis
added
area-System.Threading.Tasks
and removed
needs-area-label
This was referenced Dec 9, 2024
Open
Closed
danmoseley
approved these changes
Dec 9, 2024
There was a problem hiding this comment.
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
Comments suppressed due to low confidence (1)
src/libraries/System.Private.CoreLib/src/System/Collections/Generic/ValueListBuilder.cs:18
- The use of the null-forgiving operator (!) on scratchBuffer is unnecessary and potentially misleading. The constructor should ensure that scratchBuffer is non-null before assignment.
_span = scratchBuffer!;
Tip: Leave feedback on Copilot's review comments with the 👎 and 👍 buttons to help improve review quality. Learn more
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
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Outdated suggestions cannot be applied.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.
When the incoming enumerable isn't a
Task[]orList<Task>, we end up allocating either aTask[]or aList<T>(which then may incur one or more array allocations under the covers). We can avoid that by using an internal builder.Closes #110530