Andrew Haley wrote:
> ffileppo wrote:
>
>> I've been investigating about performance of java code compiled with gcj on embedded systems.
>> In particular I'm interested in testing AWT/SWING application using GTK/Xorg as graphical backend
>> (this is the only viable solution since QT peers are not well supported).
>>
>> The embedded device I've been using for testing is a PXA270 processor (armv5te) equipped with 128Mb Ram;
>> running linux kernel 2.6.24 and using libgcj.so.10. GTK peers are running on Xorg, using matchbox
>> as window manager. The crosscompiler on my host is gcc 4.4.
>>
>> During my tests I've noticed that java code using AWT/SWING (for example the test case attached at the end)
>> with GTK peer cause a very high load on the cpu.
>> Furthermore the applications take a lot of time to load and also the UI responsiveness is very slow.
>> Using "top" I can see that CPU is always at 100% during start up (it takes about 2 minutes
>> to get the application starting, Ram usage is ok).
>>
>> I've also noticed that using optimizations (-O2, -O3...) does not help with graphical performance.
>>
>> [On the same device, running WinCE and a commerical JVM (CrEme), applications have extremely better
>> graphical performance]
>>
>> From my experience with this particual embedded system I can say that gcj has very high performance
>> when dealing with non-gui tasks (e.g. array sorting) compared with most of JVMs but gui
>> performance are very poor.
>>
>> I would like to ask your opinion about the slowness of gui applications in my setup,
>> and also about viable solutions to improve this issue.
>> What do you think is the bottleneck?
>>
>> -- libgcj itself?
>> -- GTK library / GTK peer implementation in classpath?
>> -- something dealing with Xorg?
>
> We can only speculate.
>
> oprofile is your friend. If you can get oprofile working on your
> target system, please use it and find out if it does what you need.
I did it. The answer is appended.
The problem is that the program is spending almost all of the time
generating stack traces, millions and millions of them.
Andrew.
259512 13.5589 libgcc_s.so.1 libgcc_s.so.1 execute_cfa_program
188702 9.8592 libgcc_s.so.1 libgcc_s.so.1 _Unwind_IteratePhdrCallback
169139 8.8371 libgcc_s.so.1 libgcc_s.so.1 uw_update_context_1
155408 8.1197 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_mark_from
113082 5.9083 libgcc_s.so.1 libgcc_s.so.1 uw_frame_state_for
77219 4.0345 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_platform_gettimeofday()
65323 3.4130 libc-2.8.so libc-2.8.so dl_iterate_phdr
61075 3.1910 no-vmlinux no-vmlinux (no symbols)
55123 2.8800 libgcc_s.so.1 libgcc_s.so.1 read_encoded_value_with_base
52303 2.7327 libpthread-2.8.so libpthread-2.8.so pthread_mutex_lock
42087 2.1989 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_add_to_black_list_normal
38694 2.0217 libpthread-2.8.so libpthread-2.8.so __pthread_mutex_unlock_usercnt
32618 1.7042 libc-2.8.so libc-2.8.so strlen
27568 1.4404 libgcc_s.so.1 libgcc_s.so.1 _Unwind_Backtrace
27246 1.4235 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_find_start
26285 1.3733 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_FindCore(_Jv_core_chain*, java::lang::String*)
24849 1.2983 libgcc_s.so.1 libgcc_s.so.1 _Unwind_Find_FDE
21328 1.1143 libc-2.8.so libc-2.8.so memset
18771 0.9807 libz.so.1.2.3 libz.so.1.2.3 deflate_slow
18318 0.9571 libgcc_s.so.1 libgcc_s.so.1 get_cie_encoding
16052 0.8387 libgcj.so.10.0.0 libgcj.so.10.0.0 __gcj_personality_v0
14649 0.7654 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_StackTrace::UnwindTraceFn(_Unwind_Context*, void*)
12847 0.6712 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_find_header
11533 0.6026 libgcc_s.so.1 libgcc_s.so.1 base_from_cb_data
10373 0.5420 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_local_gcj_malloc
9712 0.5074 libc-2.8.so libc-2.8.so memcpy
9000 0.4702 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_IsAssignableFrom(java::lang::Class*, java::lang::Class*)
8478 0.4430 libgcc_s.so.1 libgcc_s.so.1 uw_update_context
8216 0.4293 libz.so.1.2.3 libz.so.1.2.3 fill_window
7534 0.3936 libfreetype.so.6.3.16 libfreetype.so.6.3.16 (no symbols)
7390 0.3861 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_MonitorExit
6617 0.3457 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_MonitorEnter
5593 0.2922 libgcj.so.10.0.0 libgcj.so.10.0.0 bool java::lang::String::equals(java::lang::Object*)
5521 0.2885 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_NewPrimArray
5130 0.2680 libgcj.so.10.0.0 libgcj.so.10.0.0 _Jv_CheckArrayStore
4780 0.2497 libgcj.so.10.0.0 libgcj.so.10.0.0 GC_clear_stack_inner
[Linux Kernel]
[Linux Cryptography]
[Fedora]
[Fedora Directory]
[Red Hat Development]
