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