Re: [cp-patches] Patch: use StringBuilder for reading/writing property files

[Anthony Green]

On Wed, 2005-10-19 at 14:53 -0700, Anthony Green wrote:
> On Wed, 2005-10-19 at 12:49 -0700, David Daney wrote:
> > You also might want to look at comment #1 of:
> > 
> > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21869
> 
> Thanks for the pointer.  I think a non-copying unsynchronized
> StringBuffer clearly makes the most sense.  I'll demonstrate the
> improvement with gcj before my next patch.

I patched the FC rawhide GCC to use gnu.gcj.runtime.StringBuffer in
java.util.Properties, and wrote a little program to read the locale
property files from GNU Classpath.   Reading the property files was
about 10% faster.

Here's oprofile output from before and after.  Note how _Jv_MonitorEnter
and _Jv_MonitorExit migrate down the list.

Adding this kind of unsynchronized StringBuffer to GNU Classpath seems
like a good idea.  (although I don't plan on doing that soon)


CPU: P4 / Xeon, speed 2400 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) 
with a unit mask of 0x01 (mandatory) count 100000
samples  %        image name               app name                 symbol name
1842      8.6268  libgcj.so.6.0.0          libgcj.so.6.0.0          
_Jv_MonitorExit
1448      6.7816  libgcj.so.6.0.0          libgcj.so.6.0.0          
_Jv_MonitorEnter
840       3.9341  libgcj.so.6.0.0          libgcj.so.6.0.0          GC_mark_from
329       1.5408  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_malloc_atomic
319       1.4940  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::util::Properties::load(java::io::InputStream*)
226       1.0584  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::StringBuffer::append(wchar_t)
200       0.9367  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::String::charAt(int)
175       0.8196  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_gcj_malloc
172       0.8055  libgcj.so.6.0.0          libgcj.so.6.0.0          
__i686.get_pc_thunk.bx
172       0.8055  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Character::isWhitespace(wchar_t)
150       0.7025  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Integer::parseInt(java::lang::String*, int, bool)
136       0.6369  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::StringBuffer::ensureCapacity_unsynchronized(int)
132       0.6182  libgcj.so.6.0.0          libgcj.so.6.0.0          .plt
119       0.5573  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Character::readChar(wchar_t)
102       0.4777  libgcj.so.6.0.0          libgcj.so.6.0.0          
gnu::gcj::convert::Input_8859_1::read(JArray<wchar_t>*, int, int)
102       0.4777  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::util::Hashtable::put(java::lang::Object*, java::lang::Object*)
101       0.4730  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::String::equals(java::lang::Object*)
74        0.3466  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Object::getClass()
73        0.3419  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::io::BufferedReader::lineEnd(int)
72        0.3372  libgcj.so.6.0.0          libgcj.so.6.0.0          
_Jv_InitClass



CPU: P4 / Xeon, speed 2400 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) 
with a unit mask of 0x01 (mandatory) count 100000
samples  %        image name               app name                 symbol name
2151     11.0836  libgcj.so.6.0.0          libgcj.so.6.0.0          GC_mark_from
869       4.4778  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_add_to_black_list_normal
411       2.1178  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::util::Properties::load(java::io::InputStream*)
390       2.0096  libgcj.so.6.0.0          libgcj.so.6.0.0          
gnu::gcj::runtime::StringBuffer::ensureCapacity(int)
359       1.8498  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_find_start
301       1.5510  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_malloc_atomic
249       1.2830  libgcj.so.6.0.0          libgcj.so.6.0.0          
__i686.get_pc_thunk.bx
233       1.2006  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::String::charAt(int)
210       1.0821  libgcj.so.6.0.0          libgcj.so.6.0.0          
GC_gcj_malloc
199       1.0254  libgcj.so.6.0.0          libgcj.so.6.0.0          .plt
172       0.8863  libgcj.so.6.0.0          libgcj.so.6.0.0          
gnu::gcj::runtime::StringBuffer::append(wchar_t)
167       0.8605  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Integer::parseInt(java::lang::String*, int, bool)
165       0.8502  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Character::isWhitespace(wchar_t)
127       0.6544  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Character::readChar(wchar_t)
113       0.5823  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::Character::digit(wchar_t, int)
101       0.5204  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::lang::String::equals(java::lang::Object*)
97        0.4998  libgcj.so.6.0.0          libgcj.so.6.0.0          
gnu::gcj::convert::Input_8859_1::read(JArray<wchar_t>*, int, int)
93        0.4792  libgcj.so.6.0.0          libgcj.so.6.0.0          
_Jv_MonitorExit
93        0.4792  libgcj.so.6.0.0          libgcj.so.6.0.0          
java::io::BufferedReader::lineEnd(int)
71        0.3658  libgcj.so.6.0.0          libgcj.so.6.0.0          
_Jv_MonitorEnter