help on instruction scheduling of hotspot jvm

[Rémi Forax]

  Le 13/09/2010 01:14, David Holmes a écrit :
> ddmetro said the following on 09/13/10 08:14:
>> I am working on multithreaded instruction scheduling on hotspot jvm. 
>> I have
>> built the source code, however I have the following doubts:
>>
>> 1. I tried to look into instruction scheduling pass of Hotspot, but 
>> couldn't
>> find any paper related to the same. Can you please direct me towards 
>> a paper
>> that talks about instruction scheduling and thread scheduling in hotspot
>> jvm.
>
> Don't know about instruction scheduling (which is a compiler issue) 
> but thread scheduling is basically done using the OS default 
> scheduling mechanism. There are some settings you can adjust to change 
> this, and you can do things externally (ie run the JVM in particular 
> scheduling class) but they are not recommended and need to be used 
> with extreme care. Dave Dice has some blog articles on this:
>
> http://blogs.sun.com/dave/entry/java_thread_priority_revisted_in
>
>> 2. I executed an applet using the j2sdk image's appletviewer. 
>> However, I am
>> not able to get the starting point (main() method) for the same. Kindly
>> provide the starting point.
>
> Applets don't have a main() method. Applets are executed by a 
> framework and it is the framework that has the main() method. You'd 
> have to look at the AppletViewer class in this case.
>
>> 3. I am assuming that the instruction scheduling will be done by the 
>> server
>> side hotspot jvm and not the compiler (C2). Kindly confirm if my
>> understanding is correct.
>
> The Hotspot "server" VM is the Hotspot VM configured to run the C2 
> compiler. (The "client" VM runs the C1 compiler). Any instruction 
> scheduling would be done by the compiler, but questions on this are 
> better addressed to hotspot-compiler-dev - cc'ed.
>
>> Also, I tried to search for documentation that maps the different
>> phases(instruction scheduling, register allocation, etc) with the source
>> code classes. However I wasn't able to find one. Kindly direct me to 
>> such
>> documentation, if one exists.
>
> There is not a lot of documentation for hotspot internals in general. 
> Again the compiler folk may be able to point you to documents or blog
> entries that discuss this.

There is a wiki:
http://wikis.sun.com/display/HotSpotInternals/Home

>
> HTH
>
> David Holmes
>
>> Thanking You,
>> -Dhiraj.

Rémi