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

[Vladimir Kozlov]

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
>>>
>>