Re-enable sun.misc.Unsafe by default on Java 24+ #15296
Merged
+1
−5
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
Motivation: In netty#14943 we disabled Unsafe by default on Java 24+, to avoid producing warnings from the JVM. However, disabling the use of Unsafe also disables the hacks we use to access `ByteBuffer` cleaners to eagerly deallocate them. This can have dire performance consequences, particularly for busy applications. Disabling the warnings from Unsafe also did nothing to stem the warnings produced by our JNI code, so many systems still see warnings anyway. We should instead revert the changed default, and just tolerate the warning in Netty 4.1. In Netty 4.2 we have netty#15231 as a long-term fix, where we avoid using Unsafe but will have a way to eagerly release the memory of our native ByteBuffer instances. Modification: Change the default for our Unsafe usage to no longer be disabled on Java 24+. Result: More consistent performance across Java versions.
normanmaurer
approved these changes
May 30, 2025
This was referenced May 30, 2025
LuciferYang
pushed a commit
to apache/spark
that referenced
this pull request
Jun 11, 2025
…e to 2.0.72.Final ### What changes were proposed in this pull request? This PR aims to Upgrade Netty to 4.1.122.Final and Netty-tcnative to 2.0.72.Final. ### Why are the changes needed? To bring the Java 24 related update and the latest bug fixes. > We decided to enable sun.misc.Unsafe by default again when using JDK24+ (when possible) as disabling it by default on this java versions did come with quite a performance regression. - https://netty.io/news/2025/06/03/4-1-122-Final.html - netty/netty#15296 - netty/netty#15248 - netty/netty#15122 ### Does this PR introduce _any_ user-facing change? No. ### How was this patch tested? Pass the CIs. ### Was this patch authored or co-authored using generative AI tooling? No. Closes #51145 from dongjoon-hyun/SPARK-52438. Authored-by: Dongjoon Hyun <dongjoon@apache.org> Signed-off-by: yangjie01 <yangjie01@baidu.com>
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.
See https://github.com/netty/netty/wiki/Java-24-and-sun.misc.Unsafe for more information.
Motivation:
In #14943 we disabled Unsafe by default on Java 24+, to avoid producing warnings from the JVM. However, disabling the use of Unsafe also disables the hacks we use to access
ByteBuffercleaners to eagerly deallocate them. This can have dire performance consequences, particularly for busy applications.Disabling the warnings from Unsafe also did nothing to stem the warnings produced by our JNI code, so many systems still see warnings anyway.
We should instead revert the changed default, and just tolerate the warning in Netty 4.1.
In Netty 4.2 we have #15231 as a long-term fix, where we avoid using Unsafe but will have a way to eagerly release the memory of our native ByteBuffer instances.
Modification:
Change the default for our Unsafe usage to no longer be disabled on Java 24+.
Result:
More consistent performance across Java versions.