[Bug java/41549] New: [jni] very slow jni code callbacks

["hermantenbrugge at home dot nl" <gcc-bugzilla at gcc dot gnu dot org>]

See mailing list:
http://gcc.gnu.org/ml/java/2009-09/msg00030.html

I have a problem with jni code callbacks.
I have attached some code that shows the problem.
The result of this code is:


# results on fedora 11
#  gcc/gcj 4.4.1
#  kernel 2.6.30.5-43.fc11.x86_64
#  openjdk fedora-29.b16.fc11-x86_64
#
#                       open jdk        gcj
# no_jni                 1.48               7.46        (  5 times slower)
# jni                   66.70           17140.00        (257 times slower)


So when not using jni in this case gcj is 5 times slower.
I suspect the jit compiler does a good for this small sample.


The code with jni calls is however 257 timer slower. I really
did not expect that. I also tried other java vm and they all
have much better performance. So I expect a problem in the
gcj library.


When I use oprofile I see at lot of calls to execute_cfa_program
and _Unwind_IteratePhdrCallback.


-- 
           Summary: [jni]  very slow jni code callbacks
           Product: gcc
           Version: 4.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: java
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hermantenbrugge at home dot nl
  GCC host triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41549