Reduce unnecessary TLS usage in JITServer code (resubmission) #19858
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Avoid using the thread-local variable TR::compInfoPT (mostly through TR::CompilationInfo::getStream()) in contexts where the compInfoPT or the Compilation is readily available. TLS accesses in dynamically loaded shared libraries (such as the JIT) can have non-negligible overhead. A resubmission of eclipse-openj9#14931. That PR also avoided using TLS in the methods of the J9::KnownObjectTable by accessing that class's comp() object to retrieve a JITServer::ServerStream. However, that is (not at all obviously) unsafe to do in that context, because some methods of the J9::KnownObjectTable may be called during the initialization of that very comp() object. Fixes: eclipse-openj9#19809 Signed-off-by: Christian Despres <[email protected]>
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Attn @mpirvu |
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jenkins test sanity,extended,sanity.system,extended.system zlinuxjit,xlinuxjit jdk17 |
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The following test failed on zlinux. Given that this test uses -Xnocompressedrefs, I think that JITServer was not used. |
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Avoid using the thread-local variable TR::compInfoPT (mostly through TR::CompilationInfo::getStream()) in contexts where the compInfoPT or the Compilation is readily available. TLS accesses in dynamically loaded shared libraries (such as the JIT) can have non-negligible overhead.
A resubmission of #14931. That PR also avoided using TLS in the methods of the J9::KnownObjectTable by accessing that class's comp() object to retrieve a JITServer::ServerStream. However, that is (not at all obviously) unsafe to do in that context, because some methods of the J9::KnownObjectTable may be called during the initialization of that very comp() object.
Fixes: #19809