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Posted to dev@harmony.apache.org by Tonny Lau <to...@gmail.com> on 2006/10/30 03:48:47 UTC
[drlvm][jit] How to override jit compilation?
Hi,
I want to override some specific java methods with native fast path
implementations. So I try to override them in
compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
I add several entries in
_stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
and lookup this table
before invoke jit->compile_method_with_params().
It works for JET, but failed when OPT recompile these method. Does the OPT
go different path? If so, how can I override it? Does anyone can help me?
Thanks,
tonny
Re: [drlvm][jit] How to override jit compilation?
Posted by Salikh Zakirov <Sa...@Intel.com>.
Mikhail Fursov wrote:
> The solutions we have today:
>
> 1) If you have only a few methods to be affected: create separate JIT
> instance without inliner and add method filters to EM configuration file.
> Check
> http://incubator.apache.org/harmony/subcomponents/drlvm/emguide.htmland
> *.emconf files for details.
>
> 2) If you need to avoid inlining of special method in all Java methods you
> can use 'skip_methods' parameter of inliner pass. See opt.emconf file to
> check how to pass parameters to inliner.
>
> 3) Replace all calls to your method with VMHelperCall in translator.
> Process
> it as direct calls in codegenerator. This solution was already proposed by
> Egor.
For the sake of completeness, there is one more solution
4) mark methods as 'native' in java sources and provide "native stub overrides" in
vmcore/src/jit/native_overrides.cpp.
Re: [drlvm][jit] How to override jit compilation?
Posted by Mikhail Fursov <mi...@gmail.com>.
Today I see several possible solutions. The complete solution with calling
arbitrary native methods from Java is not ready: we are just discussing it
in a separate thread. The first step of calling arbitrary native calls from
Java is VM helpers inlining framework. I'm going to commit it today and will
notify you about JIRA num. I hope it will serve as example.
The solutions we have today:
1) If you have only a few methods to be affected: create separate JIT
instance without inliner and add method filters to EM configuration file.
Check http://incubator.apache.org/harmony/subcomponents/drlvm/emguide.htmland
*.emconf files for details.
2) If you need to avoid inlining of special method in all Java methods you
can use 'skip_methods' parameter of inliner pass. See opt.emconf file to
check how to pass parameters to inliner.
3) Replace all calls to your method with VMHelperCall in translator. Process
it as direct calls in codegenerator. This solution was already proposed by
Egor.
--
Mikhail Fursov
Re: [drlvm][jit] How to override jit compilation?
Posted by Egor Pasko <eg...@gmail.com>.
On the 0x212 day of Apache Harmony Tonny Lau wrote:
> 30 Oct 2006 11:03:50 +0600, Egor Pasko <eg...@gmail.com>:
> >
> > On the 0x212 day of Apache Harmony Tonny Lau wrote:
> > > Hi,
> > >
> > > I want to override some specific java methods with native fast path
> > > implementations. So I try to override them in
> > > compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
> > > I add several entries in
> > >
> > _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
> > > and lookup this table
> > > before invoke jit->compile_method_with_params().
> >
> > This mechanism is not used (AFAIR and AFAICanSeeNow). The alternative
> > way is to support your "magics" within each JIT. (Mikhail does things
> > like that in OPT just from JavaByteCodeTranslator.cpp (see
> > isMagicClass(...))
>
>
> Thanks! I'll look it.
>
> > It works for JET, but failed when OPT recompile these method. Does the OPT
> > > go different path? If so, how can I override it? Does anyone can help
> > me?
> >
> > how does it fail? did you try it with -Xem:opt? (That's what I tend
> > to always ask about:)
> >
> > Just a guess: OPT expects some profile from JET, but cannot find any.
>
>
> I mean, the overriding succeeds when I use JET only, i.e., "java -
> Dem.properties=jet ...". If I use the default configuration "java ...", at
> the beginning, the overriding is successful because the code is compiled by
> JET. But later, when the EM invoke OPT to re-compile the hot code, the
> overriding does not work any longer. It fall back to the original java code.
yeah, that looks much like inlining :) hence, fixable in the inliner
> So, where do you think is the best place in OPT for the overriding
> code?
I suppose overriding==your-custom-native-code? Can your code be
written using ordinary (address) arithmetic and simple mem
allocations?
If so, then the best method is to write it in Java using
*org.vmmagic.unboxed* package that Mikhail has just
implemented. Otherwise you can hack around
JavaByteCodeTranslator::invokevirtual and recognize your "magic"
methods there, replacing the method's invokation with your custom IR.
>And is there a common path for both JET and OPT?
No. Especially when you take OPT's inlining into
consideration. OPT can inline using only OPTs mechanisms that JET is
not aware of.
But *org.vmmagic.unboxed* can help you since it is supported both in
JET and OPT.
--
Egor Pasko, Intel Managed Runtime Division
Re: [drlvm][jit] How to override jit compilation?
Posted by Tonny Lau <to...@gmail.com>.
30 Oct 2006 11:03:50 +0600, Egor Pasko <eg...@gmail.com>:
>
> On the 0x212 day of Apache Harmony Tonny Lau wrote:
> > Hi,
> >
> > I want to override some specific java methods with native fast path
> > implementations. So I try to override them in
> > compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
> > I add several entries in
> >
> _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
> > and lookup this table
> > before invoke jit->compile_method_with_params().
>
> This mechanism is not used (AFAIR and AFAICanSeeNow). The alternative
> way is to support your "magics" within each JIT. (Mikhail does things
> like that in OPT just from JavaByteCodeTranslator.cpp (see
> isMagicClass(...))
Thanks! I'll look it.
> It works for JET, but failed when OPT recompile these method. Does the OPT
> > go different path? If so, how can I override it? Does anyone can help
> me?
>
> how does it fail? did you try it with -Xem:opt? (That's what I tend
> to always ask about:)
>
> Just a guess: OPT expects some profile from JET, but cannot find any.
I mean, the overriding succeeds when I use JET only, i.e., "java -
Dem.properties=jet ...". If I use the default configuration "java ...", at
the beginning, the overriding is successful because the code is compiled by
JET. But later, when the EM invoke OPT to re-compile the hot code, the
overriding does not work any longer. It fall back to the original java code.
So, where do you think is the best place in OPT for the overriding code? And
is there a common path for both JET and OPT?
>
--
> Egor Pasko, Intel Managed Runtime Division
>
>
Re: [drlvm][jit] How to override jit compilation?
Posted by Egor Pasko <eg...@gmail.com>.
On the 0x212 day of Apache Harmony Tonny Lau wrote:
> Hi,
>
> I want to override some specific java methods with native fast path
> implementations. So I try to override them in
> compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
> I add several entries in
> _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
> and lookup this table
> before invoke jit->compile_method_with_params().
This mechanism is not used (AFAIR and AFAICanSeeNow). The alternative
way is to support your "magics" within each JIT. (Mikhail does things
like that in OPT just from JavaByteCodeTranslator.cpp (see isMagicClass(...))
> It works for JET, but failed when OPT recompile these method. Does the OPT
> go different path? If so, how can I override it? Does anyone can help me?
how does it fail? did you try it with -Xem:opt? (That's what I tend
to always ask about:)
Just a guess: OPT expects some profile from JET, but cannot find any.
--
Egor Pasko, Intel Managed Runtime Division
Re: [drlvm][jit] How to override jit compilation?
Posted by Alex Astapchuk <al...@gmail.com>.
Tonny Lau wrote:
> 2006/10/30, Alex Astapchuk <al...@gmail.com>:
>>
>> Tonny,
>>
>> Tonny Lau wrote:
>> > Hi,
>> >
>> > I want to override some specific java methods with native fast path
>> > implementations. So I try to override them in
>> > compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
>> > I add several entries in
>> >
>> _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
>>
>> >
>> > and lookup this table
>> > before invoke jit->compile_method_with_params().
>> >
>> > It works for JET, but failed when OPT recompile these method. Does the
>> OPT
>> > go different path?
>>
>> I suppose it's because OPT inlines the methods of your interest, so they
>> simply do not go through the VM's compilation machinery.
>>
>> > If so, how can I override it? Does anyone can help me?
>>
>> Try to turn off inlining in OPT - will it help?
>
>
> You're right. It works for OPT after I disable inline. :)
> But there is a performance regression when the compiler switch to OPT. I'll
> continue the investigation. Thanks!
Well, I don't see much options here rather than do the overriding in the
OPT codebase.
VM guys may correct me here:
As far as I remember, the VM had a special machinery to override the
methods [1].
if memory serves, the method entries were handled on class preparation
- somewhere at [2]. So the JIT 'saw' them as native and did not try to
inline them. Seems very close to the functionality you need.
However after a quick look on the latest srcs, it seems the machinery is
not used anymore.
[1] Have a look at the end of vmcore\src\util\ia32\base\compile_IA32.cpp
- it's the table for the methods handles in a special way.
[2] vmcore\src\class_support\Prepare.cpp
--
Thanks,
Alex
Re: [drlvm][jit] How to override jit compilation?
Posted by Tonny Lau <to...@gmail.com>.
2006/10/30, Alex Astapchuk <al...@gmail.com>:
>
> Tonny,
>
> Tonny Lau wrote:
> > Hi,
> >
> > I want to override some specific java methods with native fast path
> > implementations. So I try to override them in
> > compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
> > I add several entries in
> >
> _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
> >
> > and lookup this table
> > before invoke jit->compile_method_with_params().
> >
> > It works for JET, but failed when OPT recompile these method. Does the
> OPT
> > go different path?
>
> I suppose it's because OPT inlines the methods of your interest, so they
> simply do not go through the VM's compilation machinery.
>
> > If so, how can I override it? Does anyone can help me?
>
> Try to turn off inlining in OPT - will it help?
You're right. It works for OPT after I disable inline. :)
But there is a performance regression when the compiler switch to OPT. I'll
continue the investigation. Thanks!
--
> Thanks,
> Alex
>
>
Re: [drlvm][jit] How to override jit compilation?
Posted by Alex Astapchuk <al...@gmail.com>.
Tonny,
Tonny Lau wrote:
> Hi,
>
> I want to override some specific java methods with native fast path
> implementations. So I try to override them in
> compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is,
> I add several entries in
> _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp),
>
> and lookup this table
> before invoke jit->compile_method_with_params().
>
> It works for JET, but failed when OPT recompile these method. Does the OPT
> go different path?
I suppose it's because OPT inlines the methods of your interest, so they
simply do not go through the VM's compilation machinery.
> If so, how can I override it? Does anyone can help me?
Try to turn off inlining in OPT - will it help?
--
Thanks,
Alex