Request for review 7178145: Change constMethodOop::_exception_table to optionally inlined u2 table
Jiangli Zhou
jiangli.zhou at oracle.com
Tue Jun 19 14:24:37 PDT 2012
Hi,
Please review the following webrev for method exception handler table
memory reduction:
http://javaweb.sfbay.sun.com/~jianzhou/webrev.exceptiontable/
Per VM spec the method exception handler table is tuples of u2's, but in
hotspot the data are stored as ints in constMethodOop::_exception_table
(a typeArray). The change reduces the exception handler table memory
usage by:
* Changing the exception handler table from int array to u2 array.
* Making the exception handler table as conditionally allocated
inlined table in constMethod, and eliminate the _exception_table
field. The inlined table is only allocated when the exception
table attribute exists for the method.
* Removing the overhead of the extra typeArray, the data is directly
stored in the inlined table when exception handler exists for a
method.
Tested with runthese, jprt and vm.quick.testlist. No noticeable
performance degradation from specjvm98 and specjbb2005.
==============================================================================
logs.exceptiontable_baseline.1:
Benchmark Samples Mean Stdev Geomean
Weight
specjbb2005 8 56372.58 763.16
specjvm98 8 534.50 19.50
==============================================================================
logs.exceptiontable.1:
Benchmark Samples Mean Stdev %Diff P
Significant
specjbb2005 8 56734.05 880.76 0.64
0.395 *
specjvm98 8 531.05 21.00 -0.65
0.738 *
==============================================================================
==============================================================================
logs.exceptiontable_baseline.2:
Benchmark Samples Mean Stdev Geomean
Weight
specjvm98 8 527.63 17.10
==============================================================================
logs.exceptiontable.2:
Benchmark Samples Mean Stdev %Diff P
Significant
specjvm98 8 536.79 20.54 1.74
0.349 *
==============================================================================
Thanks,
Jiangli
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/attachments/20120619/0cdf3d3e/attachment.html
More information about the hotspot-runtime-dev
mailing list