RFR: 8296301: Interpreter(RISC-V): Implement -XX:+PrintBytecodeHistogram and -XX:+PrintBytecodePairHistogram options [v2]

[Fei Yang]

On Thu, 10 Nov 2022 12:36:36 GMT, Yanhong Zhu <yzhu at openjdk.org> wrote:

>> In this patch, count_bytecode() is modified by using "x7" as temporary register. Also implement histogram_bytecode() and histogram_bytecode_pair(), which can be enabled on debug mode by setting the options PrintBytecodeHistogram and PrintBytecodePairHistogram.
>> 
>> The following is the output when PrintBytecodeHistogram or PrintBytecodePairHistogram is TRUE.
>> 
>> $ java -XX:+PrintBytecodeHistogram --version|head -n 20
>> openjdk 20 2022-11-09
>> OpenJDK Runtime Environment (fastdebug build 20)
>> OpenJDK 64-Bit Server VM (fastdebug build 20, mixed mode)
>> 
>> Histogram of 8101142 executed bytecodes:
>> 
>>   absolute  relative  code    name
>> ----------------------------------------------------------------------
>>     634592     7.83%    dc    fast_aload_0
>>     471840     5.82%    b6    invokevirtual
>>     376275     4.64%    2b    aload_1
>>     358520     4.43%    e0    fast_iload
>>     332267     4.10%    de    fast_aaccess_0
>>     270189     3.34%    a7    goto
>>     249831     3.08%    19    aload
>>     223361     2.76%    b9    invokeinterface
>>     215666     2.66%    1c    iload_2
>>     194877     2.41%    b8    invokestatic
>>     192212     2.37%    2c    aload_2
>>     185826     2.29%    1b    iload_1
>> 
>> $ java -XX:+PrintBytecodePairHistogram --version|head -n 20
>> openjdk 20 2022-11-09
>> OpenJDK Runtime Environment (fastdebug build 20)
>> OpenJDK 64-Bit Server VM (fastdebug build 20, mixed mode)
>> 
>> Histogram of 7627721 executed bytecode pairs:
>> 
>>   absolute  relative    codes    1st bytecode        2nd bytecode
>> ----------------------------------------------------------------------
>>     102673    1.346%    84 a7    iinc                goto
>>      85429    1.120%    dc 2b    fast_aload_0        aload_1
>>      84394    1.106%    dc b6    fast_aload_0        invokevirtual
>>      73131    0.959%    b7 dc    invokespecial       fast_aload_0
>>      64605    0.847%    2b b6    aload_1             invokevirtual
>>      64086    0.840%    dc b9    fast_aload_0        invokeinterface
>>      63663    0.835%    b6 dc    invokevirtual       fast_aload_0
>>      59946    0.786%    b6 de    invokevirtual       fast_aaccess_0
>>      56631    0.742%    36 e0    istore              fast_iload
>>      51261    0.672%    b9 de    invokeinterface     fast_aaccess_0
>>      49556    0.650%    3a 19    astore              aload
>>      49106    0.644%    a7 e0    goto                fast_iload
>> 
>> The items in column "relative" are equal to percentages of bytecodes in the result of the TraceBytecodes option(counting bytecodes manually).
>
> Yanhong Zhu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   replace atomic_addalw with atomic_addw

Updated change looks good. Thanks.

-------------

Marked as reviewed by fyang (Reviewer).

PR: https://git.openjdk.org/jdk/pull/11051