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what is meant by "application doesnt work on 'green thread' jvm"?

 
Maulin Vasavada
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hi all,
i know little about green threads. green threads work at application level as there is no mapping to the OS level threads.
my question is- when some application specification says that it doesn't run on JVMs that is based on "Green Thread", what does it really mean?
my guess to the answer is- as JVM supports only Green Threads, the application can't make promises about the application behavior due to the uncertainty in the Green Threads execution. Hence they say, the application won't work (rather than saying- it will misbehave may be?)
please help me ...
regards
maulin
 
John Smith
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My understanding is that some earlier releases of JVMs had the "many threads to one thread" multithreading model where instead of mapping a user thread into an underlying OS thread, the JVM managed these thread internally, with its own scheduler, where the user threads were queued and mapped to one OS thread, one at a time. That resulted in severe performance problems, inability to make use of multiple processors, etc.
As far as I know, this "green threads" model has been replaced by the many-to-many model since then.
 
Maulin Vasavada
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hi Eugene,
what u say makes sense! i wish we get more insights on this...
Jim...Michael...William....Cindy...Paul...where r u...?? would u leave this ranch hand alone, in the maze of green/native threads, starving to survive?? just ("key",Ding) :-)
regards
maulin
 
Peter den Haan
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It probably means that they couldn't be bothered to stick yield() calls in long-running threads. As a consequence, a single thread can monopolise the CPU and starve out all others. Unless they did something really stupid, it will probably not malfunction on green thread JVMs, it will just be unusable.
By the way -- do not make the mistake of thinking that bartenders and sheriffs are necessarily the most knowledgeable ranchers.
- Peter
[ April 25, 2003: Message edited by: Peter den Haan ]
 
Maulin Vasavada
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hi Peter...
sorry...i didnt really mean bartenders r most knowledgable or offend others in this way....i just threw in some names i'm most famailar with and unfortunately they turned out to be bartenders or sheriffs...
i didnt really mean rest ranchers r dumb as it includes me as well
btw, thanks of the answer. i was having similar doubt about s/w that said they might not work on green thread jvms..now i guess i am satisfied with what i know...
regards
maulin.
 
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