Re: [yocto] Tuning for a machine based on Cortex-A9

2016-08-24 Thread Khem Raj 

> On Aug 24, 2016, at 12:51 AM, Ottavio Campana  wrote:
> 
> Hello,
> 
> I am trying to port a third-party BSP based on buildroot to yocto, but I am 
> not able to tune the compiler to extactly match the original one.
> 
> Particularly, if I run readelf on a binary compiled with the gcc that is used 
> by buildroot I get this output
> 
> ottavio@ottavio:~$ readelf -A hello_world
> Attribute Section: aeabi
> File Attributes
>   Tag_CPU_name: "Cortex-A9"
>   Tag_CPU_arch: v7
>   Tag_CPU_arch_profile: Application
>   Tag_ARM_ISA_use: Yes
>   Tag_THUMB_ISA_use: Thumb-2
>   Tag_FP_arch: VFPv3
>   Tag_Advanced_SIMD_arch: NEONv1
>   Tag_ABI_PCS_wchar_t: 4
>   Tag_ABI_FP_rounding: Needed
>   Tag_ABI_FP_denormal: Needed
>   Tag_ABI_FP_exceptions: Needed
>   Tag_ABI_FP_number_model: IEEE 754
>   Tag_ABI_align_needed: 8-byte
>   Tag_ABI_align_preserved: 8-byte, except leaf SP
>   Tag_ABI_enum_size: int
>   Tag_CPU_unaligned_access: v6
>   Tag_MPextension_use: Allowed
>   Tag_Virtualization_use: TrustZone
> ottavio@ottavio:~$
> 
> I tried to replicate this by configuring a new machine, and my machine 
> configuration looks like this
> 
> require ../../../meta/conf/machine/include/tune-cortexa9.inc
> 
> AVAILTUNES += "cortexa9t-vfpv3-neon"
> ARMPKGARCH_tune-cortexa9t-vfpv3-neon  = "cortexa9"
> TUNE_FEATURES_tune-cortexa9t-vfpv3-neon   = 
> "${TUNE_FEATURES_tune-armv7at-vfpv3} neon cortexa9"
> PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon = 
> "${PACKAGE_EXTRA_ARCHS_tune-armv7at-vfpv3} cortexa9-vfp cortexa9-vfpv3 
> cortexa9t2-vfp cortexa9t2-vfpv3 cortexa9-neon"
> 
> DEFAULTTUNE = "cortexa9t-vfpv3-neon”

Use

 DEFAULTTUNE = "cortexa9t-neon"

if you want to use hard-float ABI then

DEFAULTTUNE = “cortexa9thf-neon"

> 
> If I run readelf on any compiled binary obtained with yocto, I get this 
> result:
> 
> ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$
>  readelf -A .libs/bzip2
> Attribute Section: aeabi
> File Attributes
>   Tag_CPU_name: "Cortex-A9"
>   Tag_CPU_arch: v7
>   Tag_CPU_arch_profile: Application
>   Tag_ARM_ISA_use: Yes
>   Tag_THUMB_ISA_use: Thumb-2
>   Tag_FP_arch: VFPv3
>   Tag_ABI_PCS_wchar_t: 4
>   Tag_ABI_FP_rounding: Needed
>   Tag_ABI_FP_denormal: Needed
>   Tag_ABI_FP_exceptions: Needed
>   Tag_ABI_FP_number_model: IEEE 754
>   Tag_ABI_align_needed: 8-byte
>   Tag_ABI_align_preserved: 8-byte, except leaf SP
>   Tag_ABI_enum_size: int
>   Tag_CPU_unaligned_access: v6
>   Tag_MPextension_use: Allowed
>   Tag_Virtualization_use: TrustZone
> ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$
> 
> I am quite close to get a similar binary, the missing part is the 
> Tag_Advanced_SIMD_arch: NEONv1 .  I get exactly the same result if I use 
> DEFAULTTUNE = "cortexa9t-vfpv3", thus it seems that the neon and 
> cortexa9-neon options I tried to add are ignored.
> 
> At this point I have two questions
> 
> Question #1
> 
> How should I change ARMPKGARCH_tune-cortexa9t-vfpv3-neon , 
> TUNE_FEATURES_tune-cortexa9t-vfpv3-neon and 
> PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon to have exactly the same kind 
> of elf?
> 
> Question # 2
> 
> Why the only options for neon in meta/conf/machine/include/tune-cortexa9.inc 
> are offered for HF tunes?
> 
> 
> Thank you for your help
> 
> Ottavio
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> 


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Re: [yocto] Tuning for a machine based on Cortex-A9

2016-08-24 Thread Lennart Sorensen 
On Wed, Aug 24, 2016 at 07:51:40AM +, Ottavio Campana wrote:
> Hello,
> 
> I am trying to port a third-party BSP based on buildroot to yocto, but I am 
> not able to tune the compiler to extactly match the original one.
> 
> Particularly, if I run readelf on a binary compiled with the gcc that is used 
> by buildroot I get this output
> 
> ottavio@ottavio:~$ readelf -A hello_world
> Attribute Section: aeabi
> File Attributes
>   Tag_CPU_name: "Cortex-A9"
>   Tag_CPU_arch: v7
>   Tag_CPU_arch_profile: Application
>   Tag_ARM_ISA_use: Yes
>   Tag_THUMB_ISA_use: Thumb-2
>   Tag_FP_arch: VFPv3
>   Tag_Advanced_SIMD_arch: NEONv1
>   Tag_ABI_PCS_wchar_t: 4
>   Tag_ABI_FP_rounding: Needed
>   Tag_ABI_FP_denormal: Needed
>   Tag_ABI_FP_exceptions: Needed
>   Tag_ABI_FP_number_model: IEEE 754
>   Tag_ABI_align_needed: 8-byte
>   Tag_ABI_align_preserved: 8-byte, except leaf SP
>   Tag_ABI_enum_size: int
>   Tag_CPU_unaligned_access: v6
>   Tag_MPextension_use: Allowed
>   Tag_Virtualization_use: TrustZone
> ottavio@ottavio:~$
> 
> I tried to replicate this by configuring a new machine, and my machine 
> configuration looks like this
> 
> require ../../../meta/conf/machine/include/tune-cortexa9.inc
> 
> AVAILTUNES += "cortexa9t-vfpv3-neon"
> ARMPKGARCH_tune-cortexa9t-vfpv3-neon  = "cortexa9"
> TUNE_FEATURES_tune-cortexa9t-vfpv3-neon   = 
> "${TUNE_FEATURES_tune-armv7at-vfpv3} neon cortexa9"
> PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon = 
> "${PACKAGE_EXTRA_ARCHS_tune-armv7at-vfpv3} cortexa9-vfp cortexa9-vfpv3 
> cortexa9t2-vfp cortexa9t2-vfpv3 cortexa9-neon"
> 
> DEFAULTTUNE = "cortexa9t-vfpv3-neon"
> 
> If I run readelf on any compiled binary obtained with yocto, I get this 
> result:
> 
> ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$
>  readelf -A .libs/bzip2
> Attribute Section: aeabi
> File Attributes
>   Tag_CPU_name: "Cortex-A9"
>   Tag_CPU_arch: v7
>   Tag_CPU_arch_profile: Application
>   Tag_ARM_ISA_use: Yes
>   Tag_THUMB_ISA_use: Thumb-2
>   Tag_FP_arch: VFPv3
>   Tag_ABI_PCS_wchar_t: 4
>   Tag_ABI_FP_rounding: Needed
>   Tag_ABI_FP_denormal: Needed
>   Tag_ABI_FP_exceptions: Needed
>   Tag_ABI_FP_number_model: IEEE 754
>   Tag_ABI_align_needed: 8-byte
>   Tag_ABI_align_preserved: 8-byte, except leaf SP
>   Tag_ABI_enum_size: int
>   Tag_CPU_unaligned_access: v6
>   Tag_MPextension_use: Allowed
>   Tag_Virtualization_use: TrustZone
> ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$
> 
> I am quite close to get a similar binary, the missing part is the 
> Tag_Advanced_SIMD_arch: NEONv1 .  I get exactly the same result if I use 
> DEFAULTTUNE = "cortexa9t-vfpv3", thus it seems that the neon and 
> cortexa9-neon options I tried to add are ignored.
> 
> At this point I have two questions
> 
> Question #1
> 
> How should I change ARMPKGARCH_tune-cortexa9t-vfpv3-neon , 
> TUNE_FEATURES_tune-cortexa9t-vfpv3-neon and 
> PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon to have exactly the same kind 
> of elf?
> 
> Question # 2
> 
> Why the only options for neon in meta/conf/machine/include/tune-cortexa9.inc 
> are offered for HF tunes?

Well it looks to me like the HF neon options imply vfp, while the vfp3
tunes imply not neon.  Since they share registers the performance may
in fact be better if they are not mixed.

Of course there exists A9's without neon, so one might want to build
for that.

The git commit that added the vfpv3 tunes says they are for 32 register
VFP on A9s.  Neon already implies 32 registers for the vfp.

As far as I can tell, you can set DEFAULTTUNE to cortexa9t-neon to get
softfp with neon support, or you can set it to cortexa9thf-neon to get
hardfp with neon support.

Certainly cortexa9t-vfpv3 should NOT do neon as far as I can tell.

Getting the output you had above with neon support in it, I believe
means doing DEFAULTTUNE=cortexa9thf-neon

There is no such option as cortexa9t-vfpv3-neon that I can find in the
files anywhere, so that wouldn't work.  No point trying to invent one
since neon implies vfpv3 already.

-- 
Len Sorensen
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[yocto] Tuning for a machine based on Cortex-A9

2016-08-24 Thread Ottavio Campana 
Hello,

I am trying to port a third-party BSP based on buildroot to yocto, but I am not 
able to tune the compiler to extactly match the original one.

Particularly, if I run readelf on a binary compiled with the gcc that is used 
by buildroot I get this output

ottavio@ottavio:~$ readelf -A hello_world
Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "Cortex-A9"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv3
  Tag_Advanced_SIMD_arch: NEONv1
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_rounding: Needed
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_align_preserved: 8-byte, except leaf SP
  Tag_ABI_enum_size: int
  Tag_CPU_unaligned_access: v6
  Tag_MPextension_use: Allowed
  Tag_Virtualization_use: TrustZone
ottavio@ottavio:~$

I tried to replicate this by configuring a new machine, and my machine 
configuration looks like this

require ../../../meta/conf/machine/include/tune-cortexa9.inc

AVAILTUNES += "cortexa9t-vfpv3-neon"
ARMPKGARCH_tune-cortexa9t-vfpv3-neon  = "cortexa9"
TUNE_FEATURES_tune-cortexa9t-vfpv3-neon   = 
"${TUNE_FEATURES_tune-armv7at-vfpv3} neon cortexa9"
PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon = 
"${PACKAGE_EXTRA_ARCHS_tune-armv7at-vfpv3} cortexa9-vfp cortexa9-vfpv3 
cortexa9t2-vfp cortexa9t2-vfpv3 cortexa9-neon"

DEFAULTTUNE = "cortexa9t-vfpv3-neon"

If I run readelf on any compiled binary obtained with yocto, I get this result:

ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$
 readelf -A .libs/bzip2
Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "Cortex-A9"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv3
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_rounding: Needed
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_align_preserved: 8-byte, except leaf SP
  Tag_ABI_enum_size: int
  Tag_CPU_unaligned_access: v6
  Tag_MPextension_use: Allowed
  Tag_Virtualization_use: TrustZone
ottavio@ottavio:~/poky/build-xxx/tmp/work/cortexa9-vfpv3-poky-linux-gnueabi/bzip2/1.0.6-r5/build$

I am quite close to get a similar binary, the missing part is the 
Tag_Advanced_SIMD_arch: NEONv1 .  I get exactly the same result if I use 
DEFAULTTUNE = "cortexa9t-vfpv3", thus it seems that the neon and cortexa9-neon 
options I tried to add are ignored.

At this point I have two questions

Question #1

How should I change ARMPKGARCH_tune-cortexa9t-vfpv3-neon , 
TUNE_FEATURES_tune-cortexa9t-vfpv3-neon and 
PACKAGE_EXTRA_ARCHS_tune-cortexa9t-vfpv3-neon to have exactly the same kind of 
elf?

Question # 2

Why the only options for neon in meta/conf/machine/include/tune-cortexa9.inc 
are offered for HF tunes?


Thank you for your help

Ottavio
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