RFR: 8339573: Update CodeCacheSegmentSize and CodeEntryAlignment for ARM

[Boris Ulasevich]

On Tue, 10 Sep 2024 10:05:09 GMT, Lutz Schmidt <lucy at openjdk.org> wrote:

> During my testing of the mentioned fixes, I never saw such long freelists.

I see the warning every time I run Renaissance benchmarks with the VerifyCodeCache option. Is this a problem and not just a reflection of the fact that the codeheap contains 20K of methods with some holes in between?


$ ./build/linux-aarch64-server-fastdebug/jdk/bin/java -XX:+VerifyCodeCache -XX:+PrintCodeCache -jar ~/renaissance-jmh-0.14.2-95-gae3b5ce.jar Dotty
# Run progress: 0.00% complete, ETA 00:00:00
# Fork: 1 of 5
# Warmup Iteration   1: 86079.453 ms/op
# Warmup Iteration   2: 8212.947 ms/op
# Warmup Iteration   3: 5416.496 ms/op
# Warmup Iteration   4: 6841.073 ms/op
# Warmup Iteration   5: 4248.337 ms/op
# Warmup Iteration   6: OpenJDK 64-Bit Server VM warning: CodeHeap: # of free blocks > 10000
3530.697 ms/op
# Warmup Iteration   7: 3186.153 ms/op


> CodeCacheSegmentSize should not be chosen too small to keep memory and processing overhead in check. 64 bytes appears to be a feasible choice.

OK. Thanks!

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PR Comment: https://git.openjdk.org/jdk/pull/20864#issuecomment-2340350586