RFR (L): 8024545: make develop and notproduct flag values available in product builds

[Vladimir Kozlov]

On 9/12/13 5:11 PM, Christian Thalinger wrote:
>
> On Sep 12, 2013, at 4:30 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>
>> Christian,
>>
>> Can you put _flags first to avoid padding between _addr and _value in 32-bit VM?
>
> Yes, good point.
>
>>
>> It would be nice enumerate flag's type and use int instead of strings:
>>
>> enum {
>>   bool_flag = 1,
>>   intx_flag = 2,
>>
>> + #define RUNTIME_PRODUCT_FLAG_STRUCT(     type, name, value, doc) { type##_flag, XSTR(name), &name,              VALUE(value), NOT_PRODUCT_ARG(doc) Flag::Flags(Flag::DEFAULT | Flag::KIND_PRODUCT) },
>
> I was thinking of putting the type into the flags, too.  That would save another pointer word.  Should I give it a shot in this change or a separate one?

Do it in separate changes after you push this.
And if you remove _type field later you don't need to move _flags now.
So you can push your current changes as it is. They are good.

Thanks,
Vladimir

>
> -- Chris
>
>>
>> Thanks,
>> Vladimir
>>
>> On 9/12/13 9:58 AM, Christian Thalinger wrote:
>>>
>>> On Sep 11, 2013, at 5:34 PM, David Holmes <david.holmes at oracle.com> wrote:
>>>
>>>> Hi Chris,
>>>>
>>>> There seems to be an awful lot "infrastructure" work needed to make something that sounds simple happen. :( All the changes to the scoping and the set/get methods tends to obscure the core change. My only suggestion here is that the "set" methods could perhaps factor this:
>>>>
>>>> +   if (is_constant_in_binary()) {
>>>> +     fatal(err_msg("flag is constant: %s", _name));
>>>>
>>>> into a check_writable() method so that it isn't duplicated so much.
>>>
>>> Good point.  I made that change:
>>>
>>> http://cr.openjdk.java.net/~twisti/8024545/webrev/src/share/vm/runtime/globals.cpp.udiff.html
>>>
>>>>
>>>> I also wonder whether a ConstFlag sub/superclass would simplify this at all?
>>>
>>> Maybe it would but then we need more infrastructure to read the additional entries.  Might be a wash.  SA only knows about offsets in structs and the flags array is statically defined.
>>>
>>>>
>>>> That aside I'm curious why the minimal VM size change is only 22K when client is 32K?
>>>
>>> The 32-bit product build also contains the server compiler.
>>>
>>> -- Chris
>>>
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>> On 11/09/2013 10:56 AM, Christian Thalinger wrote:
>>>>> http://cr.openjdk.java.net/~twisti/8024545/webrev/
>>>>>
>>>>> 8024545: make develop and notproduct flag values available in product builds
>>>>> Reviewed-by:
>>>>>
>>>>> Right now the internal flag table only contains flags which are defined in a product build. This does not include develop and notproduct flags. Sometimes it is useful to have access to these values for post-mortem core file analysis or to read these values for compiler settings for a Java-based compiler.
>>>>>
>>>>> This change enables develop and notproduct flag values to be read by the serviceability agent. The binary size is increased by 42k for a 64-bit product build and by 32k for a 32-bit product build.
>>>>>
>>>>> Before:
>>>>>
>>>>> $ java -cp /java/re/jdk/8/latest/binaries/linux-x64/lib/sa-jdi.jar sun.jvm.hotspot.CLHSDB 9399
>>>>> Attaching to process 9399, please wait...
>>>>> hsdb> flags -nd
>>>>> InitialHeapSize = 495006528 5
>>>>> MaxHeapSize = 7920943104 5
>>>>> UseCompressedKlassPointers = true 5
>>>>> UseCompressedOops = true 5
>>>>> UseParallelGC = true 5
>>>>> hsdb> flags InlineMathNatives
>>>>> Couldn't find flag: InlineMathNatives
>>>>>
>>>>> After:
>>>>>
>>>>> $ java -cp $JAVA_HOME/lib/sa-jdi.jar sun.jvm.hotspot.CLHSDB 3726
>>>>> Attaching to process 3726, please wait...
>>>>> hsdb> flags -nd
>>>>> InitialHeapSize = 495006528 5
>>>>> MaxHeapSize = 7920943104 5
>>>>> UseCompressedKlassPointers = true 5
>>>>> UseCompressedOops = true 5
>>>>> UseParallelGC = true 5
>>>>> hsdb> flags InlineMathNatives
>>>>> InlineMathNatives = true 0
>>>>>
>>>>> This patch has one behavioral difference; when printing flags with e.g. PrintFlagsFinal in a debug build it prints "develop" for develop flags:
>>>>>
>>>>>      uintx AdaptiveSizePolicyGCTimeLimitThreshold    = 5               {develop}
>>>>>
>>>>> The output for product builds is unchanged.
>>>>>
>>>
>