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Re: [arm-gnu] cs 2010q1 toolchain generates slower code than 2007q3?

  • To: Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>
  • Subject: Re: [arm-gnu] cs 2010q1 toolchain generates slower code than 2007q3?
  • From: Jauder Ho <codecrumb@xxxxxxxxx>
  • Date: Fri, 25 Jun 2010 13:26:34 -0700
Maxim,

Out of curiosity, I compiled the Pre kernel with both the 2007q3 (Palm
compiles their kernel with this) and the 2010q1-202 toolchains. (compiled
with Os -mcpu=cortex-a8 -mtune=cortex-a8 -march=armv7-a)

The kernel compiled with 2007q3 works just fine and just a tad faster. While
both kernels compiled and booted, it turns out that the kernel compiled with
2010q1 caused 3D games to stop working. Tried a couple variations with the
same result.

I also tried coremark compiled with -mfloat-abi=soft and -mfloat-abi=softfp.
softfp threw a floating point exception.

Just a couple of data points.



On Wed, Jun 23, 2010 at 11:13 AM, Maxim Kuvyrkov <maxim@xxxxxxxxxxxxxxxx>wrote:

> On 6/22/10 11:20 AM, codecrumb wrote:
> ...
>
>  As a quick test, I decided to use c linpack. Since the Pre is a
>> cortex-a8, I ended up compiling with "-Os -mcpu=cortex-a8
>> -mtune=cortex-a8 -march=armv7-a -mfpu=neon -mfloat-abi=softfp".
>>
>
> Could you give a try to the following set of options:
>
> For performance:
> * -O2 -mcpu=cortex-a8
> * -O2 -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp
>
> For size:
> * -Os -mcpu=cortex-a8 -mthumb
> * -Os -mcpu=cortex-a8 -mthumb -mfpu=neon -mfloat-abi=softfp
>
> If there are significant (>5%) speed of size degradation on any of these
> options, please let us know.  As usual, initial analysis of the regressions
> are much appreciated.
>
> Thank you,
>
> --
> Maxim Kuvyrkov
> CodeSourcery
> maxim@xxxxxxxxxxxxxxxx
> (650) 331-3385 x724
>