
Ubuntu 12.04 ARM Performance Becomes Very Compelling - 6ren
http://www.phoronix.com/scan.php?page=article&item=ubuntu_1204_omap4460&num=1
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DarkShikari
A lot of applications used on ARM may still be crippled due to lack of NEON
assembly code. Many number-crunching applications, like compression, have lots
of MMX/SSE SIMD on x86, but no NEON, and will likely be slow on ARM until they
do.

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nextparadigms
What do you mean? All dual core ARM chips and above (except Tegra 2) have
NEON. Also all 1 Ghz and above Snapdragon chips.

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newman314
Most smartphones now are armv7 and have been for the last 2 years or so.

I don't see an issue with a baseline being set for armv7+vfp+neon being a
minimum processor feature set going forward for mobile devices (phones &
tablets)

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justincormack
Well the hardfloat stuff was clearly worthwhile, but some meaningful
benchmarks against x86 would be more useful. My ARM machines are all faster
than my terrible Atom, but a lot slower than anything modern for cpu intensive
benchmarks.

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agrover
how long does it take to compile the linux kernel?

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av500
It takes "ages", but that is mainly due to the very slow mass storage speed
that current ARM SoCs feature. Mobile phones and development boards like the
Pandaboard use SD cards as mass storage and SD cards can be very slow when not
used for typically linear read/write operations in your digital camera

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anoother
Do you have any data to back this up? I have compiled kernels on an ARMv5
device off a (I believe PCI-e-hosted) 7200rpm SATA hard disk, and it _is_
slow.

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av500
I have only anecdotal evidence from people that are masochistic enough to
compile their stuff natively, I prefer to cross-build.

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newman314
This particular set of benchmarks are misleading as more of the performance
comes from a faster CPU clock speed. For a more accurate feel, look at the
middle set of numbers.

That said, hardfp looks to be a definite gain over softfp and really should
have been deployed by distributions when the Cortex-A8 generation of
processors became available.

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av500
There are very few hardfp benchmarks that really compare just this feature and
leave the rest of the system identical. E.g. comparing Debian armv5 with
floating point emulation vs Ubuntu armv7hf of course yields a huge gain, but
that mainly is not due to the fact that floating point values are now passed
in fp registers.

If SW relies heavily on passing a handful of floating point values in function
calls, it should be rewritten to use NEON/SIMD on ARM - and then all you pass
is a pointer to the data, regardless of the calling convention. And once you
move to writing the mission critical stuff in assembly, you can chose your own
calling convention for subroutines as you see fit anyway.

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dsr_
For reference, this is the same CPU as the Galaxy Nexus, run at the same
clockspeeds.

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nextparadigms
Cortex A15 and DDR3 for ARM should really start to make the ARM architecture
very compelling for (low-end) laptops with very high battery life. And they're
both arriving this year.

