RFR: 8295023: Interpreter(AArch64): Implement -XX:+PrintBytecodeHistogram and -XX:+PrintBytecodePairHistogram options

[Hao Sun]

In this patch, we implement functions histogram_bytecode() and histogram_bytecode_pair() for interpreter AArch64 part. Similar to count_bytecode(), we use atomic operations to update the counters as well.

Here shows part of the message produced with -XX:+PrintBytecodeHistogram and -XX:+PrintBytecodePairHistogram options after this patch.


$ java -XX:+PrintBytecodeHistogram --version | head -20
openjdk 20-internal 2023-03-21
OpenJDK Runtime Environment (fastdebug build 20-internal-adhoc.haosun.jdk-src-dev)
OpenJDK 64-Bit Server VM (fastdebug build 20-internal-adhoc.haosun.jdk-src-dev, mixed mode)

Histogram of 5004099 executed bytecodes:

  absolute  relative  code    name
----------------------------------------------------------------------
    319124     6.38%    dc    fast_aload_0
    313397     6.26%    e0    fast_iload
    251436     5.02%    b6    invokevirtual
    227428     4.54%    19    aload
    166054     3.32%    a7    goto
    159167     3.18%    2b    aload_1
    151803     3.03%    de    fast_aaccess_0
    136787     2.73%    1b    iload_1
    124037     2.48%    36    istore
    118791     2.37%    84    iinc
    118121     2.36%    1c    iload_2
    110484     2.21%    a2    if_icmpge

$ java -XX:+PrintBytecodePairHistogram --version | head -20
openjdk 20-internal 2023-03-21
OpenJDK Runtime Environment (fastdebug build 20-internal-adhoc.haosun.jdk-src-dev)
OpenJDK 64-Bit Server VM (fastdebug build 20-internal-adhoc.haosun.jdk-src-dev, mixed mode)

Histogram of 4804441 executed bytecode pairs:

  absolute  relative    codes    1st bytecode        2nd bytecode
----------------------------------------------------------------------
     77602    1.615%    84 a7    iinc                goto
     49749    1.035%    36 e0    istore              fast_iload
     48931    1.018%    e0 10    fast_iload          bipush
     46294    0.964%    e0 b6    fast_iload          invokevirtual
     42661    0.888%    a7 e0    goto                fast_iload
     42243    0.879%    3a 19    astore              aload
     40138    0.835%    19 b9    aload               invokeinterface
     36617    0.762%    dc 2b    fast_aload_0        aload_1
     35745    0.744%    b7 dc    invokespecial       fast_aload_0
     35384    0.736%    19 b6    aload               invokevirtual
     35035    0.729%    b6 de    invokevirtual       fast_aaccess_0
     34667    0.722%    dc b6    fast_aload_0        invokevirtual


In order to verfiy the correctness, I took the trace information produced by -XX:+TraceBytecodes as a cross reference. The hit times for some bytecodes/bytecode pairs can be obtained via parsing the trace. Then I compared the hit times with the corresponding "absolute" columns. I randomly selected several bytecodes/bytecode pairs, and the manual comparion results showed that "absolute" columns are correct.

Note-1: count_bytecode() is updated. 1) caller-saved registers are used as temporary registers and there is no need to save/restore them. 2) atomic_addw() should be used since the counter is of int type.

Note-2: As shown by the update in file templateInterpreterGenerator.cpp, function histogram_bytecode() should be invoked only inside !PRODUCT scope.

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

Commit messages:
 - 8295023: Interpreter(AArch64): Implement -XX:+PrintBytecodeHistogram and -XX:+PrintBytecodePairHistogram options

Changes: https://git.openjdk.org/jdk/pull/10642/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10642&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295023
  Stats: 40 lines in 2 files changed: 28 ins; 7 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/10642.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10642/head:pull/10642

PR: https://git.openjdk.org/jdk/pull/10642