Integrated: 8293019: [JVMCI] change ratio of libgraal to C1 threads and use one isolate per libgraal thread

[Doug Simon]

On Wed, 31 Aug 2022 07:27:57 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> [JDK-8242440](https://bugs.openjdk.org/browse/JDK-8242440) allows the VM to use one isolate per libgraal thread (OIPLT). This has a number of benefits such better isolation of compiler crashes and avoids GC interference between isolates. Experimentation has shown that reducing the ratio of libgraal threads to C1 threads also helps keep the max RSS down. This PR makes OIPLT the default and adds a `JVMCINativeLibraryThreadFraction` flag for configuring the libgraal to C1 thread ratio. The default value for `JVMCINativeLibraryThreadFraction` is `0.33` which means there are 2 C1 threads per libgraal thread.

This pull request has now been integrated.

Changeset: 3c1bda4b
Author:    Doug Simon <dnsimon at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/3c1bda4bc3ad81ebabdd9ae05de53ff16f555027
Stats:     23 lines in 3 files changed: 18 ins; 0 del; 5 mod

8293019: [JVMCI] change ratio of libgraal to C1 threads and use one isolate per libgraal thread

Reviewed-by: never, iveresov

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PR: https://git.openjdk.org/jdk/pull/10094