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Re: locks on X86
- To: Bryce McKinlay <bryce at albatross dot co dot nz>
- Subject: Re: locks on X86
- From: Jeff Sturm <jsturm at one-point dot com>
- Date: Wed, 14 Mar 2001 19:16:54 -0500 (EST)
- cc: "Boehm, Hans" <hans_boehm at hp dot com>, "'green at redhat dot com'" <green at redhat dot com>, java at gcc dot gnu dot org, drepper at redhat dot com
On Wed, 14 Mar 2001, Bryce McKinlay wrote:
> Couldn't we change the calling convention so that synchronization happens
> _before_ making a synchronized call?
What about C++ code that invokes a synchronized Java method?
> This wont help for code which uses a
> synchronized block inside the method rather than the synchronized modifier, but
> presumably the modifier is a common case. There is a speed-size tradeoff of
> course, but synchronizing first gives a lot more opportunity for optimizations
> without inlining (synchronizing once for consecutive calls to the same object,
> moving synchronization out of a loop, etc).
Method inlining would also give opportunities to merge synchronization,
or even elminate it if the compiler can prove that an object is not shared
with other threads. I'm not sure if either is a legal optimization
though.
Jeff