Optimised ARM assembler loop

[Edward Nevill]

Hi all,

 

I have now completed converting the bytecodeInterpreterOpt.cpp in my previous email into hand crafted ARM assembler and uploaded to my PPA.

 

This gives approx 100% performance improvement over the original Zero.

 

I have conditionalised both sets of optimisations (the generic C optimisations and the Asm optimisations) so they only build on ARM.

 

The conditionalisation is in

 

ports/hotspot/build/linux/makefiles/zero.make

 

# Not included in includeDB because it has no dependencies

ifdef ICEDTEA_ZERO_BUILD

# ECN - For the time being HOTSPOT_OPT only enabled for ARM

# CFLAGS += -DHOTSPOT_OPT

ifeq ($(ZERO_LIBARCH),arm)

Obj_Files += bytecodeInterpreter_arm.o

  CFLAGS += -DHOTSPOT_OPT -DHOTSPOT_ASM

endif

endif

 

If you want to try out the generic optimisations uncomment the CFLAGS += -DHOTSPOT_OPT line.

 

Note: You will also need to update debian/rules or you wont even get the patches. Unconditionalise the lines

 

  ifneq (,$(filter $(DEB_HOST_ARCH),armel i386))
    DISTRIBUTION_PATCHES += \
        debian/patches/zero-port-opt-new.diff \
        debian/patches/zero-hotspot-opt-new.diff
  endif
 
(Of course, if you are running on an ARM platform you don't need to do this).

 

The main change was the addition of the the asm loop, however there were a few minor changes....

(note these are additional changes to those described in my previous document).

 

-          Added a rule to openjdk/hotspot/make/linux/makefiles/rules.make

o   This allows compilation of .S to .o

-          In openjdk/hotspot/src/share/vm/interpreter/bytecodeInterpreter.cpp

o   Added conditionalisation to turn HOTSPOT_OPT off when build jvmti

o   Changed run_opt so it no longer takes a strange 'bmb' argument and always returns 0

§  The adition is now always to re-execute the bytecode regardless of why it failed (eg exception etc). bytecodeInterpreterOpt.cpp is responsible for putting the world back in a state where the bytecode can be re-executed.

 

Sources available in...

 

https://launchpad.net/~enevill/+archive/ppa

 

openjdk-6-6b14-0ubuntu14~ed01

 

Binaries available RSN,

 

Regards,

Ed.

 

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