[release/9.0-staging] Revert "Remove custom allocator." #118279
+101
−0
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Backport of #117949 to release/9.0-staging
/cc @ericstj
Customer Impact
The performance of compression on .NET 9.0 was degraded in large production applications running on Windows with many concurrent operations. We tracked down the cause of the regression as due to heap fragmentation and increased CPU time spent when trying to allocate memory in zlib-ng.
Regression
Regression introduced in .NET 9.0 RC2 -- c62bc5b #105771
Testing
Benchmark created, verified fixed with the change. Customer validated fix as well.
Benchmarks will be added to performance repo if they can be made reliable. This issue issue is difficult to test as it relies on stress scenarios.
Risk
Low. We've done a lot of validation of this. We've shipped with this functionality present in the past.