

LuaJIT for ARM now in Git head: benchmarks - xearl
http://luajit.org/performance_arm.html

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dgl
There are claims that ARM's "Jazelle RCT"[1] technology could improve JIT (and
not limited to Java). Anyone know if that's just marketing or if there could
be worthwhile speedups from this on more recent cores?

[1]:
[http://wiki.tiprocessors.com/index.php/Cortex-A8_Features#Ja...](http://wiki.tiprocessors.com/index.php/Cortex-A8_Features#Jazelle_RCT_Acceleration)

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mikemike
IMHO Jazelle and ThumbEE are just marketing gimmicks.

Jazelle was (is?) half-proprietary and is only useful for a really stupid Java
bytecode interpreter. Nowadays, Java is JIT-compiled with much better
performance.

And ThumbEE came way too late for it to be useful. It requires setup/teardown,
doesn't work well with existing code and adds several other complications. It
has very few features that may be of use for any VM that has already undergone
some basic optimizations.

Believe me, you don't want to waste your time with this.

------
wmf
Too bad ARM11 is an ancient processor.

It would be interesting to see LuaJIT vs. Dalvik.

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dkersten
What are you talking about!?

Firstly, ARM11 is an instruction set and not a processor in itself. Secondly,
Mvidia Tegra[1] is an ARM11 processor and the Qualcomm MSM7201A which LuaJIT
targets seems to be Qualcomm's current generation of mobile chipsets[2].

Doesn't sound ancient to me at all. Sounds pretty current actually. Sure, I'd
like an ARM7 version of LuaJIT (specifically, for Cortex-A9 MPCore), but this
is still an interesting start. Also, now that theres an ARM11 port, its not
too far of a stretch to think that ARM7 might follow sometime in the nearish
future.

[1] <http://en.wikipedia.org/wiki/Nvidia_Tegra>

[2]
[http://www.qualcomm.com/products_services/chipsets/mobile_pr...](http://www.qualcomm.com/products_services/chipsets/mobile_processors.html)

~~~
wmf
The instruction sets have a v in them, like ARMv5, ARMv6, etc. The latest
version is ARMv7. ARM11 is a core, and has since been obsoleted by the Cortex
A8 which has been obsoleted by the Cortex A9 (e.g. Tegra 2 uses Cortex A9).

The MSM7201A is anything but current; it was used in the T-Mobile G1 from
2008.

~~~
dkersten
Cortex A9 came out last year, that doesn't automatically make all ARM11 based
processors, as you said, an "ancient processor".

2008 may not be the latest tech, but its not exactly "ancient" either. The
majority of PC owners use processors older than that. Hell, the computer I'm
typing this on is running on a 2006 Core 2. Definitely not current, but
ancient is going a bit far since it still runs quite competitively for all but
the most demanding tasks.

