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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: Wed, 23 Mar 2016 10:59:28 -0700
- Subject: Re: [PATCH x86_64] Update memcpy, mempcpy and memmove selection order for Excavator CPU BZ #19583
- Authentication-results: sourceware.org; auth=none
- References: <SN1PR12MB073325E2FB320E3CECD22660978B0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOo_pgS7Vh1+JGWiYbHr3yXZmRDpxaLX6Xs9dzHr-TSH1A at mail dot gmail dot com> <SN1PR12MB0733B252EEDF7DE08EE91AF9978B0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOqhAUNhvD0=FZm23MDeVMRaYrnkZ51wWB1O4JRu8o2ywg at mail dot gmail dot com> <SN1PR12MB07332500CE527AA6EAC1C360978C0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOqGKGsWHsM1NO7L46QdtMALoG_Wq3mahg=beWSesAg0jg at mail dot gmail dot com> <SN1PR12MB0733A07FB69B2EC3831FB091978C0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOoYXJQWB_T0SOM9+vj38yTndYknBZyjU3MbdAyc9x+g8A at mail dot gmail dot com> <SN1PR12MB0733522F9520520B45459C24978C0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOqpbUF2m40pxjyr+O8pSrA9EmUgNsOcBPuP-wDaMqn+RQ at mail dot gmail dot com> <CAMe9rOr11s9j7i4Gk2yozXY-MWJLKpFXCKkFqoLW553tyJ4LZg at mail dot gmail dot com> <SN1PR12MB0733C372AE1AFC950CFBBF44978C0 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOot+1NehTWA-LAurcZwQ-gmtvDzwHBPVro3cadAjsmALA at mail dot gmail dot com> <SN1PR12MB0733773BDA66FEA09901455C97800 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOqWa8Ni7Tw1-OaAHemNajq+r0jymcgDeSrvLudYgw7sFA at mail dot gmail dot com> <SN1PR12MB0733A805A49D7DC1F945BF8297800 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com> <CAMe9rOqTJA-LHeJEck82_3g-ezD2q-BB-jHs1puFLaugPWu=zA at mail dot gmail dot com> <SN1PR12MB07339536A92E3475A46C113B97810 at SN1PR12MB0733 dot namprd12 dot prod dot outlook dot com>
On Wed, Mar 23, 2016 at 3:12 AM, Pawar, Amit <Amit.Pawar@amd.com> wrote:
>> Then we should add Fast_Unaligned_Copy and only use it in memcpy.
> PFA patch and ChangeLog files containing fix for memcpy IFUNC function. Is it OK else please suggest for any required changes.
>
It isn't OK. Try this.
--
H.J.
From 327aadf6348bd41d1fae46ee7780e214c0a493c1 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 23 Mar 2016 10:33:19 -0700
Subject: [PATCH] [x86] Add a feature bit: Fast_Unaligned_Copy
On AMD processors, memcpy optimized with unaligned SSE load is
slower than emcpy optimized with aligned SSSE3 while other string
functions are faster with unaligned SSE load. A feature bit,
Fast_Unaligned_Copy, is added to select memcpy optimized with
unaligned SSE load.
[BZ #19583]
* sysdeps/x86/cpu-features.c (init_cpu_features): Set
Fast_Unaligned_Copy with Fast_Unaligned_Load for Intel
processors. Set Fast_Copy_Backward for AMD Excavator
processors.
* sysdeps/x86/cpu-features.h (bit_arch_Fast_Unaligned_Copy):
New.
(index_arch_Fast_Unaligned_Copy): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check
Fast_Unaligned_Copy instead of Fast_Unaligned_Load.
---
sysdeps/x86/cpu-features.c | 14 +++++++++++++-
sysdeps/x86/cpu-features.h | 3 +++
sysdeps/x86_64/multiarch/memcpy.S | 2 +-
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index c8f81ef..de75c79 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -153,8 +153,12 @@ init_cpu_features (struct cpu_features *cpu_features)
#if index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
# error index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
#endif
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+#endif
cpu_features->feature[index_arch_Fast_Unaligned_Load]
|= (bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop
| bit_arch_Slow_SSE4_2);
break;
@@ -183,10 +187,14 @@ init_cpu_features (struct cpu_features *cpu_features)
#if index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
# error index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
#endif
+#if index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
+# error index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
+#endif
cpu_features->feature[index_arch_Fast_Rep_String]
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Copy_Backward
| bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);
break;
}
@@ -220,10 +228,14 @@ init_cpu_features (struct cpu_features *cpu_features)
if (family == 0x15)
{
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+#endif
/* "Excavator" */
if (model >= 0x60 && model <= 0x7f)
cpu_features->feature[index_arch_Fast_Unaligned_Load]
- |= bit_arch_Fast_Unaligned_Load;
+ |= (bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Copy_Backward);
}
}
else
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index e06eb7e..bfe1f4c 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -35,6 +35,7 @@
#define bit_arch_I686 (1 << 15)
#define bit_arch_Prefer_MAP_32BIT_EXEC (1 << 16)
#define bit_arch_Prefer_No_VZEROUPPER (1 << 17)
+#define bit_arch_Fast_Unaligned_Copy (1 << 18)
/* CPUID Feature flags. */
@@ -101,6 +102,7 @@
# define index_arch_I686 FEATURE_INDEX_1*FEATURE_SIZE
# define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1*FEATURE_SIZE
# define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1*FEATURE_SIZE
+# define index_arch_Fast_Unaligned_Copy FEATURE_INDEX_1*FEATURE_SIZE
# if defined (_LIBC) && !IS_IN (nonlib)
@@ -265,6 +267,7 @@ extern const struct cpu_features *__get_cpu_features (void)
# define index_arch_I686 FEATURE_INDEX_1
# define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1
# define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1
+# define index_arch_Fast_Unaligned_Copy FEATURE_INDEX_1
#endif /* !__ASSEMBLER__ */
diff --git a/sysdeps/x86_64/multiarch/memcpy.S b/sysdeps/x86_64/multiarch/memcpy.S
index 8882590..5b045d7 100644
--- a/sysdeps/x86_64/multiarch/memcpy.S
+++ b/sysdeps/x86_64/multiarch/memcpy.S
@@ -42,7 +42,7 @@ ENTRY(__new_memcpy)
HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
jnz 2f
lea __memcpy_sse2_unaligned(%rip), %RAX_LP
- HAS_ARCH_FEATURE (Fast_Unaligned_Load)
+ HAS_ARCH_FEATURE (Fast_Unaligned_Copy)
jnz 2f
lea __memcpy_sse2(%rip), %RAX_LP
HAS_CPU_FEATURE (SSSE3)
--
2.5.5
- 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
- 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