llvm dev - Feb 2013 - [LLVMdev] RE : Is there any llvm neon intrinsic that maps to vmla.f32 instruction ?

On 12 February 2013 16:56, Sebastien DELDON-GNB <sebastien.deldon at
st.com>wrote:
> If this helps taking your decision, there are at least two benchmarks for
> which disabling vmlx-forwarding makes a significant difference.
>
I think Evan's worry was to base this decision on visible and
comprehensible benchmarks, such as the test-suite.


If I get lucky I may be able to run on a panda board by next week and
have
> more info to share
>
That'd be great, thanks!

--renato
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Hi Sebastien,

How many extra vmlas did you see in 433.milc due to disabling
-vmlx-forwarding?
As I mentioned earlier, I saw only two additional integer vmlx instructions
when I tested.

Could you send me your 433.milc compile setup? (os, flags, compiler
version, etc.). I'd like to try to reproduce your results.

Cheers,
Lang.


On Tue, Feb 12, 2013 at 9:05 AM, Renato Golin <renato.golin at
linaro.org>wrote:
> On 12 February 2013 16:56, Sebastien DELDON-GNB <sebastien.deldon at
st.com>wrote:
>
>> If this helps taking your decision, there are at least two benchmarks
for
>> which disabling vmlx-forwarding makes a significant difference.
>>
>
> I think Evan's worry was to base this decision on visible and
> comprehensible benchmarks, such as the test-suite.
>
>
> If I get lucky I may be able to run on a panda board by next week and have
>> more info to share
>>
>
> That'd be great, thanks!
>
> --renato
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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Hi Lang,

I'm speaking about 64-fp vmla. Find attached to this e-mail, a .ll file that
exhibits problem encountered in MILC.
I've built LLVM (trunk & 3.2) on a x86-64 Ubuntu 10.04 LTS system.
Try 
llc  -march=arm -mcpu=cortex-a9  vmlx_ex.ll -o vmlx_ex.s
and
llc  -march=arm -mcpu=cortex-a9 -mattr=-vmlx-forwarding vmlx_ex.ll -o vmlx_ex.s

You should see difference and trust me it make significant difference in
performance - at least on my platform - on MILC and other FP intensive code.

Best Regards
Seb


________________________________________
De : Lang Hames [lhames at gmail.com]
Date d'envoi : mercredi 13 février 2013 08:31
À : Renato Golin
Cc : Sebastien DELDON-GNB; llvmdev at cs.uiuc.edu
Objet : Re: [LLVMdev] RE : Is there any llvm neon intrinsic that maps to
vmla.f32 instruction ?

Hi Sebastien,

How many extra vmlas did you see in 433.milc due to disabling -vmlx-forwarding?
As I mentioned earlier, I saw only two additional integer vmlx instructions when
I tested.

Could you send me your 433.milc compile setup? (os, flags, compiler version,
etc.). I'd like to try to reproduce your results.

Cheers,
Lang.


On Tue, Feb 12, 2013 at 9:05 AM, Renato Golin <renato.golin at
linaro.org<mailto:renato.golin at linaro.org>> wrote:
On 12 February 2013 16:56, Sebastien DELDON-GNB <sebastien.deldon at
st.com<mailto:sebastien.deldon at st.com>> wrote:
If this helps taking your decision, there are at least two benchmarks for which
disabling vmlx-forwarding makes a significant difference.

I think Evan's worry was to base this decision on visible and comprehensible
benchmarks, such as the test-suite.


If I get lucky I may be able to run on a panda board by next week and have more
info to share

That'd be great, thanks!

--renato

_______________________________________________
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LLVMdev at cs.uiuc.edu<mailto:LLVMdev at cs.uiuc.edu>        
http://llvm.cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

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Hi Lang & Renato,

I eventually set up a panda board with latest linaro delivery (eabi-hf). I did
some experiments using my own compiler and LLVM 3.2 as back-end.
I use same flagset for my compiler (front-end) and just invoke llc with and
without vmlx-forwarding attribute. So base arguments to llc are:

llc  -march=arm -mcpu=cortex-a9 -mattr=+neon -float-abi=hard

to which I added -mattr=-vmlx-forwarding to disable vmlx forwarding for
cortex-a9.
When I DISABLE vmlx forwarding I'm observing a 7% speed-up on ref dataset
for MILC. So I'm observing something similar to what I've observed on
STE platform available on SNOWBALL board.

Hope this helps
Best Regards
Seb


From: Lang Hames [mailto:lhames at gmail.com]
Sent: Wednesday, February 13, 2013 8:31 AM
To: Renato Golin
Cc: Sebastien DELDON-GNB; llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] RE : Is there any llvm neon intrinsic that maps to
vmla.f32 instruction ?

Hi Sebastien,

How many extra vmlas did you see in 433.milc due to disabling -vmlx-forwarding?
As I mentioned earlier, I saw only two additional integer vmlx instructions when
I tested.

Could you send me your 433.milc compile setup? (os, flags, compiler version,
etc.). I'd like to try to reproduce your results.

Cheers,
Lang.

On Tue, Feb 12, 2013 at 9:05 AM, Renato Golin <renato.golin at
linaro.org<mailto:renato.golin at linaro.org>> wrote:
On 12 February 2013 16:56, Sebastien DELDON-GNB <sebastien.deldon at
st.com<mailto:sebastien.deldon at st.com>> wrote:
If this helps taking your decision, there are at least two benchmarks for which
disabling vmlx-forwarding makes a significant difference.

I think Evan's worry was to base this decision on visible and comprehensible
benchmarks, such as the test-suite.


If I get lucky I may be able to run on a panda board by next week and have more
info to share

That'd be great, thanks!

--renato

_______________________________________________
LLVM Developers mailing list
LLVMdev at cs.uiuc.edu<mailto:LLVMdev at cs.uiuc.edu>        
http://llvm.cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

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