8169001: Remove launcher's built-in ergonomics (original) (raw)

David Holmes david.holmes at oracle.com
Mon Nov 7 23:24:33 UTC 2016

Hi Kumar,

On 8/11/2016 4:47 AM, Kumar Srinivasan wrote:

Hello, Please review the fix for: https://bugs.openjdk.java.net/browse/JDK-8169001 Webrev at: http://cr.openjdk.java.net/~ksrini/8169001/webrev.00/

Overall this looks like a complete eradication of the launcher ergonomics. A few specific comments:

src/java.base/share/native/launcher/main.c

! const_cpwildcard, const_javaw, 0);

Can you clarify this change with

! const_cpwildcard, const_javaw, 0 /* unused */);

Thanks.

src/java.base/share/native/libjli/java.c

220 jint ergo /* unused */

I assume JLI_Launch is an exported API otherwise I'd expect this to be deleted. The fact it is unused should also be documented in src/java.base/share/native/libjli/java.h. But I'm also wondering where this API change is being documented for external users?

Not clear why you no longer need to free here. But if you don't then FreeKnownVMs() seems to be dead code now.

src/java.base/unix/conf/i586/jvm.cfg

I think you still need an entry for "-client KNOWN" as anyone can build the client VM if they choose. Ditto for src/java.base/unix/conf/sparc/jvm.cfg (though 32-bit Solaris builds are obsolete now).

You have updated a number of copyright notices but not all of them.

I see no changes to tests, but I'm pretty sure we have a test for server-class-machine somewhere (or we did - I recall it breaking at some point).

Thanks, David

Background:

Launcher ergonomics was introduced last decade to help determine if the execution system is "Server Class", this was necessary to choose server VM on platforms that supported both client and server VMs (primarily for Solaris and Linux 32-bit).

The algorithm involves computing and detecting the number of CPUs and the amount of memory on the target system. All modern computers systems with hyper-threading cause the ergonomics to choose server. JDK9 Platforms that have only server vm. ./linux-x64/lib/amd64/server/libjvm.so ./linux-arm64-vfp-hflt/lib/aarch64/server/libjvm.so ./solaris-sparcv9/lib/sparcv9/server/libjvm.so ./solaris-x64/lib/amd64/server/libjvm.so ./windows-x86/bin/server/jvm.dll ./windows-x64/bin/server/jvm.dll JDK9 Platforms that have more than one vm variant: ./linux-arm32-vfp-hflt/lib/arm/client/libjvm.so (default) ./linux-arm32-vfp-hflt/lib/arm/minimal/libjvm.so ./linux-x86/lib/i386/server/libjvm.so (default) ./linux-x86/lib/i386/minimal/libjvm.so

In the cases where multiple VMs are supported the ergnomics has no effect, and the default platforms are chosen by the jvm.cfg. Thus the launcher ergonomics is obsolete and redundant. Thanks Kumar

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