Add instrumentation in the TemplateInterpreter

[Khanh Nguyen]

I am doing interpreter-only mode currently.
Instrumentation for C1/C2, I think can be done by modifying the file
oops/oop.inline.hpp::oop_store()
On Feb 19, 2016 10:18 AM, "Christian Thalinger" <
christian.thalinger at oracle.com> wrote:

>
> On Feb 18, 2016, at 1:43 PM, Khanh Nguyen <ktruong.nguyen at gmail.com>
> wrote:
>
> Yes, you are correct. This is for a research project. We try to remember
> those references so that later we can do something similar to a GC to
> update the references. The base assumption is that we only have a small
> number of these kind of object so the cost should be acceptable.
>
> A side reason for staying with the TemplateInterpreter is that I can't
> convince my team to switch to BytecodeInterpreter in ZeroShark. The unknown
> performance of ZeroShark is partially responsible for my unability to
> convince them.
>
>
> Are you running your experiments interpreted only or in a tiered
> environment with C1/C2?
>
> On Feb 18, 2016 2:50 PM, "Christian Thalinger" <
> christian.thalinger at oracle.com> wrote:
>
>>
>> On Feb 18, 2016, at 9:30 AM, Khanh Nguyen <ktruong.nguyen at gmail.com>
>> wrote:
>>
>> The main reason is the performance difference between the
>> TemplateInterpreter and the BytecodeInterpreter in Zero.
>> I did not verify the difference but I found from this mailing list that
>> the difference is 10x.
>>
>>
>> But the instrumentation you are adding is quite expensive and I’m
>> assuming this is for research or academia?
>>
>> And since we are talking about Zero. How much is the performance
>> difference between ZeroShark and the standard Hotspot, do you by any chance
>> know?
>>
>> Thanks
>> On Feb 18, 2016 11:14 AM, "Christian Thalinger" <
>> christian.thalinger at oracle.com> wrote:
>>
>>> Can you share the reason?
>>>
>>> On Feb 18, 2016, at 8:01 AM, Khanh Nguyen <ktruong.nguyen at gmail.com>
>>> wrote:
>>>
>>> Unfortunately it has to be the Template Interpreter.
>>> On Feb 18, 2016 9:27 AM, "Christian Thalinger" <
>>> christian.thalinger at oracle.com> wrote:
>>>
>>>> Does it have to be the template interpreter or could you do your work
>>>> with Zero as well?
>>>>
>>>> > On Feb 9, 2016, at 11:19 PM, Khanh Nguyen <ktruong.nguyen at gmail.com>
>>>> wrote:
>>>> >
>>>> > Hello,
>>>> >
>>>> > I want to add instrumentation to monitor all reads and writes in the
>>>> > TemplateInterpreter, I think I got the correct place for it in
>>>> > /cpu/x86/vm/templateTable_x86_64.cpp. Can someone please tell me if
>>>> I'm
>>>> > doing it right?
>>>> >
>>>> > For writes:
>>>> > static void do_oop_store(InterpreterMacroAssembler* _masm,
>>>> >                         Address obj,
>>>> >                         Register val,
>>>> >                         BarrierSet::Name barrier,
>>>> >                         bool precise) {
>>>> > [...]
>>>> > case BarrierSet::CardTableModRef:
>>>> >  case BarrierSet::CardTableExtension:
>>>> >      {
>>>> >        if (val == noreg) {
>>>> >          __ store_heap_oop_null(obj);
>>>> >        } else {
>>>> >          __ store_heap_oop(obj, val);
>>>> >
>>>> > /*mycodeA*/  __ movptr(c_rarg1, obj.base()); // save this value
>>>> otherwise
>>>> > it will be changed?
>>>> >
>>>> >          // flatten object address if needed
>>>> >          if (!precise || (obj.index() == noreg && obj.disp() == 0)) {
>>>> >            __ store_check(obj.base());
>>>> > /*mycodeB*/ __ call_VM(noreg, //void
>>>> >                       CAST_FROM_FN_PTR(address,
>>>> >
>>>> InterpreterRuntime::write_helper),
>>>> >                       c_rarg1,  // obj
>>>> >                       c_rarg1, // field address because store check is
>>>> > called on field address
>>>> >                       val);
>>>> >          } else {
>>>> >            __ leaq(rdx, obj);
>>>> >            __ store_check(rdx);
>>>> > /*mycodeC*/ __ call_VM(noreg, //void
>>>> >                         CAST_FROM_FN_PTR(address,
>>>> >
>>>> InterpreterRuntime::write_helper),
>>>> >                         c_rarg1,  // obj
>>>> >                         rdx, // field address, because store check is
>>>> > called on field address
>>>> >                         val);
>>>> >        }
>>>> >      }
>>>> >      break;
>>>> >
>>>> > For reads:
>>>> > case Bytecodes::_fast_agetfield:
>>>> >    __ load_heap_oop(rax, field);
>>>> >
>>>> > /*mycodeD*/     __ call_VM(noreg,
>>>> >               CAST_FROM_FN_PTR(address,
>>>> >
>>>> InterpreterRuntime::read_barrier_helper),
>>>> >               rax);
>>>> >
>>>> > __ verify_oop(rax);
>>>> >    break;
>>>> >
>>>> > My questions are:
>>>> >
>>>> > 1) I thought this represents a putfield a.f=b where a.f is
>>>> represented by
>>>> > the parameter obj of type Address. b is obvious the parameter val of
>>>> type
>>>> > Register. Especially in obj there are fields: base, index and disp.
>>>> But as
>>>> > I run this, looks like obj is actually the field address. (the case
>>>> mycodeB)
>>>> > I haven't found a test case that can trigger the case mycodeC to see
>>>> the
>>>> > behavior (i.e., rdx might get destroyed and I got random value back or
>>>> > c_rarg1 is the obj address and rdx is field address)
>>>> >
>>>> > 2) Before this, I tried to insert the same __ call_VM in
>>>> fast_aputfield
>>>> > before do_oop_store but it results in JVM crash. I don't understand
>>>> the
>>>> > reason why. What I did in the call is just print the parameters. I
>>>> did see
>>>> > the values printed (only the 1st time it goes to the method) but then
>>>> the
>>>> > VM crashed. I thought __ call_VM will preserve all registers's value
>>>> and
>>>> > restore properly when comes back. My instrumentation has no side
>>>> effect, I
>>>> > just observe and record the values (actually just printing the values
>>>> to
>>>> > test).
>>>> >
>>>> > 3) Is it strictly required to have the line /*mycodeA*/ I tried to, in
>>>> > mycodeB line, pass obj.base() twice and it got build errors for
>>>> "smashed
>>>> > args"?
>>>> >
>>>> > I greatly appreciate your time,
>>>> >
>>>> > Best,
>>>> >
>>>> > Khanh Nguyen
>>>
>>>
>