[9] RFR (S) 8148639: Some MethodCounter fields can be excluded when not including C2

[Vladimir Kozlov]

On 3/25/16 12:45 PM, Chris Plummer wrote:
> Hi Vladimir,
>
> [Sorry about the delay. I was looking on hotspot-comp for comments. Forgot I also posted to hotspot-dev.]
>
> Yes, I can make that change and was already debating between two approaches. Do you also want me to pull
> interpreter_invocation_counter_offset() and interpreter_invocation_counter_offset_in_bytes() into the main
> #if/#else/#endif section? I think maybe they are best left as-is or they will be separated from other XXX_offset() methods.

Move them together and use their own #if/#else/#endif section.

Thanks,
Vladimir

>
> thanks,
>
> Chris
>
> On 3/22/16 3:11 PM, Vladimir Kozlov wrote:
>> About changes. I don't like changes in methodCounters.hpp (other files are fine).
>>
>> May be combine methods under one #if instead of separate #if per method.
>>
>> Thanks,
>> Vladimir
>>
>> On 3/22/16 3:01 PM, Vladimir Kozlov wrote:
>>> On 3/22/16 2:10 PM, Chris Plummer wrote:
>>>> Hi Vladimir,
>>>>
>>>> I just noticed that there are already about 50 occurrences of:
>>>>
>>>> #if defined(COMPILER2) || INCLUDE_JVMCI
>>>
>>> I know about that. I thought I can use you to fix it ;)
>>>
>>>>
>>>> Should I just leave my changes as-is to be consistent?
>>>
>>> Okay, if you don't want to do that I am fine with that.
>>>
>>> I filed RFE:
>>> https://bugs.openjdk.java.net/browse/JDK-8152470
>>>
>>> Thanks,
>>> Vladimir
>>>
>>>>
>>>> thanks,
>>>>
>>>> Chris
>>>>
>>>> On 3/21/16 6:09 PM, Chris Plummer wrote:
>>>>> Ok. That sounds like a good idea.
>>>>>
>>>>> thanks,
>>>>>
>>>>> Chris
>>>>>
>>>>> On 3/21/16 5:02 PM, Vladimir Kozlov wrote:
>>>>>> Chris can you also replace:
>>>>>>
>>>>>> #if defined(COMPILER2) || INCLUDE_JVMCI
>>>>>>
>>>>>> with
>>>>>>
>>>>>> #if COMPILER2_OR_JVMCI
>>>>>>
>>>>>> where
>>>>>>
>>>>>> // COMPILER2 or JVMCI
>>>>>> #if defined(COMPILER2) || INCLUDE_JVMCI
>>>>>> #define COMPILER2_OR_JVMCI 1
>>>>>>
>>>>>> Thanks,
>>>>>> Vladimir
>>>>>>
>>>>>> On 3/21/16 4:53 PM, Chris Plummer wrote:
>>>>>>> Hello,
>>>>>>>
>>>>>>> Please review the following for removing a couple of MethodCounter fields when not including C2 (or JVMCI) in the
>>>>>>> build.
>>>>>>> This helps reduce footprint for the minimal VM (and the client VM also).
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~cjplummer/8148639/webrev.03/webrev.hotspot/
>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8148639
>>>>>>>
>>>>>>> There were a couple of changes the previously were in JDK-8147978 that I had to add to this webrev since
>>>>>>> JDK-8147978 was
>>>>>>> backed out. They include making ProfileInterpreter related options unsupported when not using C2, and also the new
>>>>>>> macros in macros.hpp.
>>>>>>>
>>>>>>> In order to make sure these counters really are not used when not using C2, I took a few safeguards. The first
>>>>>>> was to
>>>>>>> make no changes other than to assert that whenever these counters are fetched, they are equal to zero. I did
>>>>>>> quite a bit
>>>>>>> of testing with this and never hit the asserts.
>>>>>>>
>>>>>>> I would have liked to #ifdef out interpreter_invocation_count() and interpreter_throwout_count(), but there are
>>>>>>> too many
>>>>>>> places that call them, which meant too many #ifdef in IMHO. So instead of #ifdef'ing them out, I just make them
>>>>>>> return 0
>>>>>>> when not using C2. This is safe because of the assert testing I did above.
>>>>>>>
>>>>>>> I do completely #ifdef out the two increment methods. interpreter_throwout_increment() is only called by some
>>>>>>> ProfileInterpreter code in bytecodeInterpreter.cpp, so I #ifdef'd that code also. In interpreterRuntime.cpp I
>>>>>>> #ifdef'd
>>>>>>> out a call to interpreter_throwout_increment(). Although this code may have been executed when not using C2, the
>>>>>>> assert
>>>>>>> testing I did above showed that if the increment happened, the counter was never used later.
>>>>>>>
>>>>>>> There are quite a few #ifdefs in methodCounters.hpp. I could collpase 5 into one big #if/#else/#endif section for
>>>>>>> all
>>>>>>> the inline method implementations. It looks cleaner, be then also puts distance between the two different
>>>>>>> versions of
>>>>>>> the same method.
>>>>>>>
>>>>>>> Testing was done with jprt "-testset hotspot". I also did a lot of testing with various tools, svc, and compiler
>>>>>>> test
>>>>>>> lists, and also runThese. This was done on linux-x86 with "-client -Xcomp" and just "-client", and also on linux-x64
>>>>>>> with "-server -XX:+TieredCompilation" (although I think that was probably the default anyway).
>>>>>>>
>>>>>>> thanks,
>>>>>>>
>>>>>>> Chris
>>>>>
>>>>
>