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Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: "Pawar, Amit" <Amit dot Pawar at amd dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Date: Fri, 18 Mar 2016 07:45:03 -0700
- Subject: Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Authentication-results: sourceware.org; auth=none
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On Fri, Mar 18, 2016 at 6:51 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Mar 18, 2016 at 6:22 AM, Pawar, Amit <Amit.Pawar@amd.com> wrote:
>>>No, it isn't fixed. Avoid_AVX_Fast_Unaligned_Load should disable __memcpy_avx_unaligned and nothing more. Also you need to fix ALL selections.
>>
>> diff --git a/sysdeps/x86_64/multiarch/memcpy.S b/sysdeps/x86_64/multiarch/memcpy.S
>> index 8882590..a5afaf4 100644
>> --- a/sysdeps/x86_64/multiarch/memcpy.S
>> +++ b/sysdeps/x86_64/multiarch/memcpy.S
>> @@ -39,6 +39,8 @@ ENTRY(__new_memcpy)
>> ret
>> #endif
>> 1: lea __memcpy_avx_unaligned(%rip), %RAX_LP
>> + HAS_ARCH_FEATURE (Avoid_AVX_Fast_Unaligned_Load)
>> + jnz 3f
>> HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
>> jnz 2f
>> lea __memcpy_sse2_unaligned(%rip), %RAX_LP
>> @@ -52,6 +54,8 @@ ENTRY(__new_memcpy)
>> jnz 2f
>> lea __memcpy_ssse3(%rip), %RAX_LP
>> 2: ret
>> +3: lea __memcpy_ssse3(%rip), %RAX_LP
>> + ret
>> END(__new_memcpy)
>>
>> # undef ENTRY
>>
>> Will update all IFUNC's if this ok else please suggest.
>>
>
> Better, but not OK. Try something like
>
> iff --git a/sysdeps/x86_64/multiarch/memcpy.S
> b/sysdeps/x86_64/multiarch/memcpy.S
> index ab5998c..2abe2fd 100644
> --- a/sysdeps/x86_64/multiarch/memcpy.S
> +++ b/sysdeps/x86_64/multiarch/memcpy.S
> @@ -42,9 +42,11 @@ ENTRY(__new_memcpy)
> ret
> #endif
> 1: lea __memcpy_avx_unaligned(%rip), %RAX_LP
> + HAS_ARCH_FEATURE (Avoid_AVX_Fast_Unaligned_Load)
> + jnz 3f
> HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
> jnz 2f
> - lea __memcpy_sse2_unaligned(%rip), %RAX_LP
> +3: lea __memcpy_sse2_unaligned(%rip), %RAX_LP
> HAS_ARCH_FEATURE (Fast_Unaligned_Load)
> jnz 2f
> lea __memcpy_sse2(%rip), %RAX_LP
>
One question. If you don't want __memcpy_avx_unaligned,
why do you set AVX_Fast_Unaligned_Load?
--
H.J.
- References:
- [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- RE: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- RE: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- RE: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- RE: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583