Hotspot loves PHP.reboot

[Rémi Forax]

On 09/05/2011 12:22 PM, Christian Thalinger wrote:
> On Sep 5, 2011, at 1:11 AM, Rémi Forax wrote:
>
>> I've just compiled the hotspot (64bits server) using the hotspot-comp
>> workspace of hotspot express (hsx)
>>   http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/
>>
>> Here are the result when running PHP.reboot on fibonacci
>> (-server is the server VM of jdk1.7.0):
>>
>> Java:
>> java -server bigfibo        4.45 s
>> java -hsx bigfibo           4.44 s
>>
>> PHP.reboot (no type annotation)
>> phpr.sh -server bigfibo    22.72 s
>> phpr.sh -hsx bigfibo       13.61 s
>>
>> PHP.reboot (type specialization)
>> phpr.sh -server bigfibo    11.09 s
>> phpr.sh -hsx bigfibo        8.06 s
>>
>> PHP.reboot (user defined type annotation)
>> phpr.sh -server bigfibo2    6.96 s
>> phpr.sh -hsx bigfibo2       4.21 s
>>
>> PHP.reboot is an hybrid runtime, it starts with an interpreter
>> that walks the AST (really slow) and then compile to bytecode.
>>
>> The first test is with no type information provided by the user,
>> so all variables are object and invokedynamic is used for the
>> operations, the comparison and for function calls.
>> As you see, there is a huge speedup.
>>
>> The second test enables a flag that ask the runtime to try to
>> specialize the function at runtime. Because the algorithm
>> used is a fast-forward typechecker, the parameter of fibo
>> is san pecialized as int but the return type is still an object
>> (because fibo is recursive).
>> So basically here, invokedynamic is used for the function calls
>> and the + between the results of the function calls.
>> This '+' is a nasty one because the two parameters are objects,
>> so it requires a double guards.
>> You can see the speedup is nice too.
>>
>> The third test uses a file that declare the parameter type and
>> return type of fibo as int, so only the function calls are done
>> using invokedynamic.
>> You can also see the speedup and weirdly it's now faster than Java
>> (not a lot if compare the value but don't forget that
>> PHP.reboot starts in interpreter mode) so it's clearly faster.
>> I will take a look to the inlining tree to try to understand why,
>> it's maybe because fibo is a recursive call or because using
>> an invokedynamic which is resolved as an invokestatic
>> enables more inlining than just an invokestatic.
>>
>> John, Christian, Tom and all the others of the hotspot-comp team,
>> you make my day :)
> These numbers make mine too :-)  Thanks for trying the current version.

No, Thank you.
Frankly, it's amazing to see how something that was at a point only
in the collective mind of the JSR 292 EG is now real and fast
thanks to your ability to massage hotspot.

> -- Christian

Rémi