Similar to BZ#19387, BZ#21014, and BZ#20971, both x86 sse2 strncat
optimized assembly implementations do not handle the size overflow
correctly.
The x86_64 one is in fact an issue with strcpy-sse2-unaligned, but
that is triggered also with strncat optimized implementation.
This patch uses a similar strategy used on 3daef2c8ee, where
saturared math is used for overflow case.
Checked on x86_64-linux-gnu and i686-linux-gnu. It fixes BZ #19390.
[BZ #19390]
* string/test-strncat.c (test_main): Add tests with SIZE_MAX as
maximum string size.
* sysdeps/i386/i686/multiarch/strcat-sse2.S (STRCAT): Avoid overflow
in pointer addition.
* sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S (STRCPY):
Likewise.
If assembler doesn't support AVX512DQ, _dl_runtime_resolve_avx is used
to save the first 8 vector registers, which only saves the lower 256
bits of vector register, for lazy binding. When it is called on AVX512
platform, the upper 256 bits of ZMM registers are clobbered. Parameters
passed in ZMM registers will be wrong when the function is called the
first time. This patch requires binutils 2.24, whose assembler can store
and load ZMM registers, to build x86-64 glibc. Since mathvec library
needs assembler support for AVX512DQ, we disable mathvec if assembler
doesn't support AVX512DQ.
[BZ #20139]
* config.h.in (HAVE_AVX512_ASM_SUPPORT): Renamed to ...
(HAVE_AVX512DQ_ASM_SUPPORT): This.
* sysdeps/x86_64/configure.ac: Require assembler from binutils
2.24 or above.
(HAVE_AVX512_ASM_SUPPORT): Removed.
(HAVE_AVX512DQ_ASM_SUPPORT): New.
* sysdeps/x86_64/configure: Regenerated.
* sysdeps/x86_64/dl-trampoline.S: Make HAVE_AVX512_ASM_SUPPORT
check unconditional.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c: Likewise.
* sysdeps/x86_64/multiarch/memcpy.S: Likewise.
* sysdeps/x86_64/multiarch/memcpy_chk.S: Likewise.
* sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S:
Likewise.
* sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memmove.S: Likewise.
* sysdeps/x86_64/multiarch/memmove_chk.S: Likewise.
* sysdeps/x86_64/multiarch/mempcpy.S: Likewise.
* sysdeps/x86_64/multiarch/mempcpy_chk.S: Likewise.
* sysdeps/x86_64/multiarch/memset-avx512-no-vzeroupper.S:
Likewise.
* sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memset.S: Likewise.
* sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_d_cos8_core_avx512.S: Check
HAVE_AVX512DQ_ASM_SUPPORT instead of HAVE_AVX512_ASM_SUPPORT.
* sysdeps/x86_64/fpu/multiarch/svml_d_exp8_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_d_log8_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_d_pow8_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_d_sin8_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_d_sincos8_core_avx512.:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_cosf16_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_expf16_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_logf16_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_powf16_core_avx512.S:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_sincosf16_core_avx51:
Likewise.
* sysdeps/x86_64/fpu/multiarch/svml_s_sinf16_core_avx512.S:
Likewise.
Although the Enhanced REP MOVSB/STOSB (ERMS) implementations of memmove,
memcpy, mempcpy and memset aren't used by the current processors, this
patch adds Prefer_ERMS check in memmove, memcpy, mempcpy and memset so
that they can be used in the future.
* sysdeps/x86/cpu-features.h (bit_arch_Prefer_ERMS): New.
(index_arch_Prefer_ERMS): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Return
__memcpy_erms for Prefer_ERMS.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
(__memmove_erms): Enabled for libc.a.
* ysdeps/x86_64/multiarch/memmove.S (__libc_memmove): Return
__memmove_erms or Prefer_ERMS.
* sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Return
__mempcpy_erms for Prefer_ERMS.
* sysdeps/x86_64/multiarch/memset.S (memset): Return
__memset_erms for Prefer_ERMS.
Since the new SSE2/AVX2 memcpy/memmove are faster than the previous ones,
we can remove the previous SSE2/AVX2 memcpy/memmove and replace them with
the new ones.
No change in IFUNC selection if SSE2 and AVX2 memcpy/memmove weren't used
before. If SSE2 or AVX2 memcpy/memmove were used, the new SSE2 or AVX2
memcpy/memmove optimized with Enhanced REP MOVSB will be used for
processors with ERMS. The new AVX512 memcpy/memmove will be used for
processors with AVX512 which prefer vzeroupper.
Since the new SSE2 memcpy/memmove are faster than the previous default
memcpy/memmove used in libc.a and ld.so, we also remove the previous
default memcpy/memmove and make them the default memcpy/memmove, except
that non-temporal store isn't used in ld.so.
Together, it reduces the size of libc.so by about 6 KB and the size of
ld.so by about 2 KB.
[BZ #19776]
* sysdeps/x86_64/memcpy.S: Make it dummy.
* sysdeps/x86_64/mempcpy.S: Likewise.
* sysdeps/x86_64/memmove.S: New file.
* sysdeps/x86_64/memmove_chk.S: Likewise.
* sysdeps/x86_64/multiarch/memmove.S: Likewise.
* sysdeps/x86_64/multiarch/memmove_chk.S: Likewise.
* sysdeps/x86_64/memmove.c: Removed.
* sysdeps/x86_64/multiarch/memcpy-avx-unaligned.S: Likewise.
* sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: Likewise.
* sysdeps/x86_64/multiarch/memmove-avx-unaligned.S: Likewise.
* sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memmove.c: Likewise.
* sysdeps/x86_64/multiarch/memmove_chk.c: Likewise.
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Remove
memcpy-sse2-unaligned, memmove-avx-unaligned,
memcpy-avx-unaligned and memmove-sse2-unaligned-erms.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list): Replace
__memmove_chk_avx512_unaligned_2 with
__memmove_chk_avx512_unaligned. Remove
__memmove_chk_avx_unaligned_2. Replace
__memmove_chk_sse2_unaligned_2 with
__memmove_chk_sse2_unaligned. Remove __memmove_chk_sse2 and
__memmove_avx_unaligned_2. Replace __memmove_avx512_unaligned_2
with __memmove_avx512_unaligned. Replace
__memmove_sse2_unaligned_2 with __memmove_sse2_unaligned.
Remove __memmove_sse2. Replace __memcpy_chk_avx512_unaligned_2
with __memcpy_chk_avx512_unaligned. Remove
__memcpy_chk_avx_unaligned_2. Replace
__memcpy_chk_sse2_unaligned_2 with __memcpy_chk_sse2_unaligned.
Remove __memcpy_chk_sse2. Remove __memcpy_avx_unaligned_2.
Replace __memcpy_avx512_unaligned_2 with
__memcpy_avx512_unaligned. Remove __memcpy_sse2_unaligned_2
and __memcpy_sse2. Replace __mempcpy_chk_avx512_unaligned_2
with __mempcpy_chk_avx512_unaligned. Remove
__mempcpy_chk_avx_unaligned_2. Replace
__mempcpy_chk_sse2_unaligned_2 with
__mempcpy_chk_sse2_unaligned. Remove __mempcpy_chk_sse2.
Replace __mempcpy_avx512_unaligned_2 with
__mempcpy_avx512_unaligned. Remove __mempcpy_avx_unaligned_2.
Replace __mempcpy_sse2_unaligned_2 with
__mempcpy_sse2_unaligned. Remove __mempcpy_sse2.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Support
__memcpy_avx512_unaligned_erms and __memcpy_avx512_unaligned.
Use __memcpy_avx_unaligned_erms and __memcpy_sse2_unaligned_erms
if processor has ERMS. Default to __memcpy_sse2_unaligned.
(ENTRY): Removed.
(END): Likewise.
(ENTRY_CHK): Likewise.
(libc_hidden_builtin_def): Likewise.
Don't include ../memcpy.S.
* sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk): Support
__memcpy_chk_avx512_unaligned_erms and
__memcpy_chk_avx512_unaligned. Use
__memcpy_chk_avx_unaligned_erms and
__memcpy_chk_sse2_unaligned_erms if if processor has ERMS.
Default to __memcpy_chk_sse2_unaligned.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
Change function suffix from unaligned_2 to unaligned.
* sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Support
__mempcpy_avx512_unaligned_erms and __mempcpy_avx512_unaligned.
Use __mempcpy_avx_unaligned_erms and __mempcpy_sse2_unaligned_erms
if processor has ERMS. Default to __mempcpy_sse2_unaligned.
(ENTRY): Removed.
(END): Likewise.
(ENTRY_CHK): Likewise.
(libc_hidden_builtin_def): Likewise.
Don't include ../mempcpy.S.
(mempcpy): New. Add a weak alias.
* sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk): Support
__mempcpy_chk_avx512_unaligned_erms and
__mempcpy_chk_avx512_unaligned. Use
__mempcpy_chk_avx_unaligned_erms and
__mempcpy_chk_sse2_unaligned_erms if if processor has ERMS.
Default to __mempcpy_chk_sse2_unaligned.
Since the new SSE2/AVX2 memsets are faster than the previous ones, we
can remove the previous SSE2/AVX2 memsets and replace them with the
new ones. This reduces the size of libc.so by about 900 bytes.
No change in IFUNC selection if SSE2 and AVX2 memsets weren't used
before. If SSE2 or AVX2 memset was used, the new SSE2 or AVX2 memset
optimized with Enhanced REP STOSB will be used for processors with
ERMS. The new AVX512 memset will be used for processors with AVX512
which prefer vzeroupper.
[BZ #19881]
* sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S: Folded
into ...
* sysdeps/x86_64/memset.S: This.
(__bzero): Removed.
(__memset_tail): Likewise.
(__memset_chk): Likewise.
(memset): Likewise.
(MEMSET_CHK_SYMBOL): New. Define only if MEMSET_SYMBOL isn't
defined.
(MEMSET_SYMBOL): Define only if MEMSET_SYMBOL isn't defined.
* sysdeps/x86_64/multiarch/memset-avx2.S: Removed.
(__memset_zero_constant_len_parameter): Check SHARED instead of
PIC.
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Remove
memset-avx2 and memset-sse2-unaligned-erms.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list): Remove __memset_chk_sse2,
__memset_chk_avx2, __memset_sse2 and __memset_avx2_unaligned.
* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
(__bzero): Enabled.
* sysdeps/x86_64/multiarch/memset.S (memset): Replace
__memset_sse2 and __memset_avx2 with __memset_sse2_unaligned
and __memset_avx2_unaligned. Use __memset_sse2_unaligned_erms
or __memset_avx2_unaligned_erms if processor has ERMS. Support
__memset_avx512_unaligned_erms and __memset_avx512_unaligned.
(memset): Removed.
(__memset_chk): Likewise.
(MEMSET_SYMBOL): New.
(libc_hidden_builtin_def): Replace __memset_sse2 with
__memset_sse2_unaligned.
* sysdeps/x86_64/multiarch/memset_chk.S (__memset_chk): Replace
__memset_chk_sse2 and __memset_chk_avx2 with
__memset_chk_sse2_unaligned and __memset_chk_avx2_unaligned_erms.
Use __memset_chk_sse2_unaligned_erms or
__memset_chk_avx2_unaligned_erms if processor has ERMS. Support
__memset_chk_avx512_unaligned_erms and
__memset_chk_avx512_unaligned.
X86-64 memset-vec-unaligned-erms.S aligns many jump targets, which
increases code sizes, but not necessarily improve performance. As
memset benchtest data of align vs no align on various Intel and AMD
processors
https://sourceware.org/bugzilla/attachment.cgi?id=9277
shows that aligning jump targets isn't necessary.
[BZ #20115]
* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S (__memset):
Remove alignments on jump targets.
Merge x86 ifunc-defines.sym with x86 cpu-features-offsets.sym. Remove
x86 ifunc-defines.sym and rtld-global-offsets.sym. No code changes on
i686 and x86-64.
* sysdeps/i386/i686/multiarch/Makefile (gen-as-const-headers):
Remove ifunc-defines.sym.
* sysdeps/x86_64/multiarch/Makefile (gen-as-const-headers):
Likewise.
* sysdeps/i386/i686/multiarch/ifunc-defines.sym: Removed.
* sysdeps/x86/rtld-global-offsets.sym: Likewise.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Likewise.
* sysdeps/x86/Makefile (gen-as-const-headers): Remove
rtld-global-offsets.sym.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Merged with ...
* sysdeps/x86/cpu-features-offsets.sym: This.
* sysdeps/x86/cpu-features.h: Include <cpu-features-offsets.h>
instead of <ifunc-defines.h> and <rtld-global-offsets.h>.
The large memcpy micro benchmark in glibc shows that there is a
regression with large data on Haswell machine. non-temporal store in
memcpy on large data can improve performance significantly. This
patch adds a threshold to use non temporal store which is 6 times of
shared cache size. When size is above the threshold, non temporal
store will be used, but avoid non-temporal store if there is overlap
between destination and source since destination may be in cache when
source is loaded.
For size below 8 vector register width, we load all data into registers
and store them together. Only forward and backward loops, which move 4
vector registers at a time, are used to support overlapping addresses.
For forward loop, we load the last 4 vector register width of data and
the first vector register width of data into vector registers before the
loop and store them after the loop. For backward loop, we load the first
4 vector register width of data and the last vector register width of
data into vector registers before the loop and store them after the loop.
[BZ #19928]
* sysdeps/x86_64/cacheinfo.c (__x86_shared_non_temporal_threshold):
New.
(init_cacheinfo): Set __x86_shared_non_temporal_threshold to 6
times of shared cache size.
* sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S
(VMOVNT): New.
* sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S
(VMOVNT): Likewise.
* sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S
(VMOVNT): Likewise.
(VMOVU): Changed to movups for smaller code sizes.
(VMOVA): Changed to movaps for smaller code sizes.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S: Update
comments.
(PREFETCH): New.
(PREFETCH_SIZE): Likewise.
(PREFETCHED_LOAD_SIZE): Likewise.
(PREFETCH_ONE_SET): Likewise.
Rewrite to use forward and backward loops, which move 4 vector
registers at a time, to support overlapping addresses and use
non temporal store if size is above the threshold and there is
no overlap between destination and source.
Prepare memmove-vec-unaligned-erms.S to make the SSE2 version as the
default memcpy, mempcpy and memmove.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
(MEMCPY_SYMBOL): New.
(MEMPCPY_SYMBOL): Likewise.
(MEMMOVE_CHK_SYMBOL): Likewise.
Replace MEMMOVE_SYMBOL with MEMMOVE_CHK_SYMBOL on __mempcpy_chk
symbols. Replace MEMMOVE_SYMBOL with MEMPCPY_SYMBOL on
__mempcpy symbols. Provide alias for __memcpy_chk in libc.a.
Provide alias for memcpy in libc.a and ld.so.
Prepare memset-vec-unaligned-erms.S to make the SSE2 version as the
default memset.
* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
(MEMSET_CHK_SYMBOL): New. Define if not defined.
(__bzero): Check VEC_SIZE == 16 instead of USE_MULTIARCH.
Disabled fro now.
Replace MEMSET_SYMBOL with MEMSET_CHK_SYMBOL on __memset_chk
symbols. Properly check USE_MULTIARCH on __memset symbols.
Since memmove and memset in ld.so don't use IFUNC, don't put SSE2, AVX
and AVX512 memmove and memset in ld.so.
* sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S: Skip
if not in libc.
* sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S:
Likewise.
__mempcpy_erms and __memmove_erms can't be placed between __memmove_chk
and __memmove it breaks __memmove_chk.
Don't check source == destination first since it is less common.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
(__mempcpy_erms, __memmove_erms): Moved before __mempcpy_chk
with unaligned_erms.
(__memmove_erms): Skip if source == destination.
(__memmove_unaligned_erms): Don't check source == destination
first.
Implement x86-64 memset with unaligned store and rep movsb. Support
16-byte, 32-byte and 64-byte vector register sizes. A single file
provides 2 implementations of memset, one with rep stosb and the other
without rep stosb. They share the same codes when size is between 2
times of vector register size and REP_STOSB_THRESHOLD which defaults
to 2KB.
Key features:
1. Use overlapping store to avoid branch.
2. For size <= 4 times of vector register size, fully unroll the loop.
3. For size > 4 times of vector register size, store 4 times of vector
register size at a time.
[BZ #19881]
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
memset-sse2-unaligned-erms, memset-avx2-unaligned-erms and
memset-avx512-unaligned-erms.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list): Test __memset_chk_sse2_unaligned,
__memset_chk_sse2_unaligned_erms, __memset_chk_avx2_unaligned,
__memset_chk_avx2_unaligned_erms, __memset_chk_avx512_unaligned,
__memset_chk_avx512_unaligned_erms, __memset_sse2_unaligned,
__memset_sse2_unaligned_erms, __memset_erms,
__memset_avx2_unaligned, __memset_avx2_unaligned_erms,
__memset_avx512_unaligned_erms and __memset_avx512_unaligned.
* sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S: New
file.
* sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S:
Likewise.
* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S:
Likewise.
Implement x86-64 memmove with unaligned load/store and rep movsb.
Support 16-byte, 32-byte and 64-byte vector register sizes. When
size <= 8 times of vector register size, there is no check for
address overlap bewteen source and destination. Since overhead for
overlap check is small when size > 8 times of vector register size,
memcpy is an alias of memmove.
A single file provides 2 implementations of memmove, one with rep movsb
and the other without rep movsb. They share the same codes when size is
between 2 times of vector register size and REP_MOVSB_THRESHOLD which
is 2KB for 16-byte vector register size and scaled up by large vector
register size.
Key features:
1. Use overlapping load and store to avoid branch.
2. For size <= 8 times of vector register size, load all sources into
registers and store them together.
3. If there is no address overlap bewteen source and destination, copy
from both ends with 4 times of vector register size at a time.
4. If address of destination > address of source, backward copy 8 times
of vector register size at a time.
5. Otherwise, forward copy 8 times of vector register size at a time.
6. Use rep movsb only for forward copy. Avoid slow backward rep movsb
by fallbacking to backward copy 8 times of vector register size at a
time.
7. Skip when address of destination == address of source.
[BZ #19776]
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
memmove-sse2-unaligned-erms, memmove-avx-unaligned-erms and
memmove-avx512-unaligned-erms.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list): Test
__memmove_chk_avx512_unaligned_2,
__memmove_chk_avx512_unaligned_erms,
__memmove_chk_avx_unaligned_2, __memmove_chk_avx_unaligned_erms,
__memmove_chk_sse2_unaligned_2,
__memmove_chk_sse2_unaligned_erms, __memmove_avx_unaligned_2,
__memmove_avx_unaligned_erms, __memmove_avx512_unaligned_2,
__memmove_avx512_unaligned_erms, __memmove_erms,
__memmove_sse2_unaligned_2, __memmove_sse2_unaligned_erms,
__memcpy_chk_avx512_unaligned_2,
__memcpy_chk_avx512_unaligned_erms,
__memcpy_chk_avx_unaligned_2, __memcpy_chk_avx_unaligned_erms,
__memcpy_chk_sse2_unaligned_2, __memcpy_chk_sse2_unaligned_erms,
__memcpy_avx_unaligned_2, __memcpy_avx_unaligned_erms,
__memcpy_avx512_unaligned_2, __memcpy_avx512_unaligned_erms,
__memcpy_sse2_unaligned_2, __memcpy_sse2_unaligned_erms,
__memcpy_erms, __mempcpy_chk_avx512_unaligned_2,
__mempcpy_chk_avx512_unaligned_erms,
__mempcpy_chk_avx_unaligned_2, __mempcpy_chk_avx_unaligned_erms,
__mempcpy_chk_sse2_unaligned_2, __mempcpy_chk_sse2_unaligned_erms,
__mempcpy_avx512_unaligned_2, __mempcpy_avx512_unaligned_erms,
__mempcpy_avx_unaligned_2, __mempcpy_avx_unaligned_erms,
__mempcpy_sse2_unaligned_2, __mempcpy_sse2_unaligned_erms and
__mempcpy_erms.
* sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S: New
file.
* sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S:
Likwise.
* sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S:
Likwise.
* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
Likwise.
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.
Chek Fast_Unaligned_Load, instead of Slow_BSF, and also check for
Fast_Copy_Backward to enable __memcpy_ssse3_back. Existing selection
order is updated with following selection order:
1. __memcpy_avx_unaligned if AVX_Fast_Unaligned_Load bit is set.
2. __memcpy_sse2_unaligned if Fast_Unaligned_Load bit is set.
3. __memcpy_sse2 if SSSE3 isn't available.
4. __memcpy_ssse3_back if Fast_Copy_Backward bit it set.
5. __memcpy_ssse3
[BZ #18880]
* sysdeps/x86_64/multiarch/memcpy.S: Check Fast_Unaligned_Load,
instead of Slow_BSF, and also check for Fast_Copy_Backward to
enable __memcpy_ssse3_back.
It shows improvement up to 28% over AVX2 memset (performance results
attached at <https://sourceware.org/ml/libc-alpha/2015-12/msg00052.html>).
* sysdeps/x86_64/multiarch/memset-avx512-no-vzeroupper.S: New file.
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Added new file.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c: Added new tests.
* sysdeps/x86_64/multiarch/memset.S: Added new IFUNC branch.
* sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
* sysdeps/x86/cpu-features.h (bit_Prefer_No_VZEROUPPER,
index_Prefer_No_VZEROUPPER): New.
* sysdeps/x86/cpu-features.c (init_cpu_features): Set the
Prefer_No_VZEROUPPER for Knights Landing.
There are configure tests for the -mavx2 compiler option. AVX2
support was added in GCC 4.7, so these tests are now obsolete; this
patch removes them.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* sysdeps/i386/configure.ac (libc_cv_cc_avx2): Remove configure
test.
* sysdeps/i386/configure: Regenerated.
* sysdeps/x86_64/configure.ac (libc_cv_cc_avx2): Remove configure
test.
* sysdeps/x86_64/configure: Regenerated.
* config.h.in (HAVE_AVX2_SUPPORT): Remove #undef.
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
memset-avx2 unconditionally instead of conditionally on
[$(config-cflags-avx2) = yes].
* sysdeps/x86_64/multiarch/ifunc-impl-list.c
(__libc_ifunc_impl_list) [HAVE_AVX2_SUPPORT]: Make code
unconditional.
* sysdeps/x86_64/multiarch/memset.S [HAVE_AVX2_SUPPORT]: Likewise.
* sysdeps/x86_64/multiarch/memset_chk.S
[IS_IN (libc) && SHARED && HAVE_AVX2_SUPPORT]: Change conditional
to [IS_IN (libc) && SHARED].
GCC added support for -msse4 in version 4.3. Thus the configure tests
for it are obsolete, and this patch removes them.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by this patch).
* sysdeps/i386/configure.ac (libc_cv_cc_sse4): Remove configure
test.
* sysdeps/i386/configure: Regenerated.
* sysdeps/i386/i686/multiarch/Makefile
[$(config-cflags-sse4) = yes]: Make code unconditional.
* sysdeps/i386/i686/multiarch/strcspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/i386/i686/multiarch/strspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/x86_64/configure.ac (libc_cv_cc_sse4): Remove configure
test.
* sysdeps/x86_64/configure: Regenerated.
* sysdeps/x86_64/multiarch/Makefile [$(config-cflags-sse4) = yes]:
Make code unconditional.
* sysdeps/x86_64/multiarch/strcspn.S [HAVE_SSE4_SUPPORT]:
Likewise.
* sysdeps/x86_64/multiarch/strspn.S [HAVE_SSE4_SUPPORT]: Likewise.
* config.h.in (HAVE_SSE4_SUPPORT): Remove #undef.
sysdeps/i386/i686/multiarch/strcasestr-c.c became unused after
commit 1818483b15
Author: Andreas Schwab <schwab@suse.de>
Date: Wed Dec 18 11:53:27 2013 +1000
Remove use of SSE4.2 functions for strstr on i686
which contains
-sysdep_routines += strcspn-c strpbrk-c strspn-c strstr-c strcasestr-c
+sysdep_routines += strcspn-c strpbrk-c strspn-c
sysdeps/x86_64/multiarch/strcasestr.c became useless after
t 584b18eb4d
Author: Ondřej Bílka <neleai@seznam.cz>
Date: Sat Dec 14 19:33:56 2013 +0100
Add strstr with unaligned loads. Fixes bug 12100.
which changes sysdeps/x86_64/multiarch/strcasestr.c to
libc_ifunc (__strcasestr, __strcasestr_sse2);
This patch removes these file.
* i386/i686/multiarch/strcasestr-c.c: Removed.
* x86_64/multiarch/strcasestr.c: Likewise.
* x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list):
Remove strcasestr.
Move sysdeps/x86_64/multiarch/init-arch.h to sysdeps/x86/init-arch.h
which can be used for both i386 and x86_64.
* sysdeps/i386/i686/multiarch/init-arch.h: Removed.
* sysdeps/unix/sysv/linux/x86/init-arch.h: Likewise.
* sysdeps/x86_64/cacheinfo.c: Include <init-arch.h> instead
of "multiarch/init-arch.h".
* sysdeps/x86_64/multiarch/init-arch.h: Renamed to ...
* sysdeps/x86/init-arch.h: This.
{memcpy,strcmp}-sse2-unaligned.S aren't needed in ld.so.
* sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: Compile
only for libc.
* sysdeps/x86_64/multiarch/strcmp-sse2-unaligned.S: Likewise.
To make a strtok faster and improve performance in general we need to do one
additional change.
A comment:
/* It doesn't make sense to send libc-internal strcspn calls through a PLT.
The speedup we get from using SSE4.2 instruction is likely eaten away
by the indirect call in the PLT. */
Does not make sense at all because nobody bothered to check it. Gap
between these implementations is quite big, when haystack is empty a
sse2 is around 40 cycles slower because it needs to populate a lookup
table and difference only increases with size. That is much bigger than
plt slowdown which is few cycles.
Even benchtest show a gap which also may be reverse by branch
misprediction but my internal benchmark shown.
simple_strspn stupid_strspn __strspn_sse42 __strspn_sse2
Length 0, alignment 0, acc len 6: 18.6562 35.2344 17.0469 61.6719
Length 6, alignment 0, acc len 6: 59.5469 72.5781 16.4219 73.625
This patch also handles strpbrk which is implemented by including a
x86_64/multiarch/strcspn.S file.
* sysdeps/x86_64/multiarch/strspn.S: Remove plt indirection.
* sysdeps/x86_64/multiarch/strcspn.S: Likewise.
memcpy with unaligned 256-bit AVX register loads/stores are slow on older
processorsl like Sandy Bridge. This patch adds bit_AVX_Fast_Unaligned_Load
and sets it only when AVX2 is available.
[BZ #17801]
* sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features):
Set the bit_AVX_Fast_Unaligned_Load bit for AVX2.
* sysdeps/x86_64/multiarch/init-arch.h (bit_AVX_Fast_Unaligned_Load):
New.
(index_AVX_Fast_Unaligned_Load): Likewise.
(HAS_AVX_FAST_UNALIGNED_LOAD): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check the
bit_AVX_Fast_Unaligned_Load bit instead of the bit_AVX_Usable bit.
* sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk): Likewise.
* sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Likewise.
* sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk): Likewise.
* sysdeps/x86_64/multiarch/memmove.c (__libc_memmove): Replace
HAS_AVX with HAS_AVX_FAST_UNALIGNED_LOAD.
* sysdeps/x86_64/multiarch/memmove_chk.c (__memmove_chk): Likewise.
In this patch we take advantage of HSW memory bandwidth, manage to
reduce miss branch prediction by avoiding using branch instructions and
force destination to be aligned with avx instruction.
The CPU2006 403.gcc benchmark indicates this patch improves performance
from 2% to 10%.
* config.h.in (HAVE_AVX2_SUPPORT): New #undef.
* sysdeps/i386/configure.ac: Set HAVE_AVX2_SUPPORT and
config-cflags-avx2.
* sysdeps/x86_64/configure.ac: Likewise.
* sysdeps/i386/configure: Regenerated.
* sysdeps/x86_64/configure: Likewise.
* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
memset-avx2 only if config-cflags-avx2 is yes.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list):
Tests for memset_chk and memset only if HAVE_AVX2_SUPPORT is
defined.
* sysdeps/x86_64/multiarch/memset.S: Define multiple versions
only if HAVE_AVX2_SUPPORT is defined.
* sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
This patch adds ifunc tests for x86_64 memset_chk and memset. It also
defines HAS_AVX2 with AVX2_Usable since AVX2 may not be usable even if
processor has AVX2.
* sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list):
Add tests for memset_chk and memset.
* sysdeps/x86_64/multiarch/init-arch.h (HAS_AVX2): Defined
with AVX2_Usable.
In this patch we take advantage of HSW memory bandwidth, manage to
reduce miss branch prediction by avoiding using branch instructions and
force destination to be aligned with avx & avx2 instruction.
The CPU2006 403.gcc benchmark indicates this patch improves performance
from 26% to 59%.
* sysdeps/x86_64/multiarch/Makefile: Add memset-avx2.
* sysdeps/x86_64/multiarch/memset-avx2.S: New file.
* sysdeps/x86_64/multiarch/memset.S: Likewise.
* sysdeps/x86_64/multiarch/memset_chk.S: Likewise.
* sysdeps/x86_64/multiarch/rtld-memset.S: Likewise.
Define FEATURE_INDEX_1 and FEATURE_INDEX_MAX as macros
for use by both assembly and C code. This fixes the
-Wundef error for cases where FEATURE_INDEX_1 was not
defined but used the correct value of 0 for an undefined
macro.
A sse42 version of strstr used pcmpistr instruction which is quite
ineffective. A faster way is look for pairs of characters which is uses
sse2, is faster than pcmpistr and for real strings a pairs we look for
are relatively rare.
For linear time complexity we use buy or rent technique which switches
to two-way algorithm when superlinear behaviour is detected.
We add new memcpy version that uses unaligned loads which are fast
on modern processors. This allows second improvement which is avoiding
computed jump which is relatively expensive operation.
Tests available here:
http://kam.mff.cuni.cz/~ondra/memcpy_profile_result27_04_13.tar.bz2
There is no problem with strcmp, it doesn't use the YMM registers.
The math routines might since gcc perhaps generates such code.
Introduce bit_YMM_USBALE and use it in the math routines.
This patch enables SSE2 memset for AMD's upcoming Orochi processor.
This patch also fixes the following bug:
For misaligned blocks larger than > 144 Bytes, memset branches into
the integer code path depending on the value of misalignment even if
the startup code chooses the SSE2 code path upfront, when multiarch
is enabled.
This patch includes optimized 64bit memcpy/memmove for Atom, Core 2 and
Core i7. It improves memcpy by up to 3X on Atom, up to 4X on Core 2 and
up to 1X on Core i7. It also improves memmove by up to 3X on Atom, up to
4X on Core 2 and up to 2X on Core i7.
This patch adds 32bit SSE4.2 string functions. It uses -16L instead of
0xfffffffffffffff0L, which works for both 32bit and 64bit long. Tested
on 32bit Core i7 and Core 2.
This patch adds multiarch support when configured for i686. I modified
some x86-64 functions to support 32bit. I will contribute 32bit SSE string
and memory functions later.
We use a callback function into libc.so to get access to the data
structure with the information and have special versions of the test
macros which automatically use this function.
The test now takes the callgraph into account. Only code called
during runtime relocation is affected by the limitation. We now
determine the affected object files as closely as possible from
the outside. This allowed to remove some the specializations
for some of the string functions as they are only used in other
code paths.
This patch introduces a test to make sure no function modifies the
xmm/ymm registers. With the exception of the auditing functions.
The test is probably too pessimistic. All code linked into ld.so
is checked. Perhaps at some point the callgraph starting from
_dl_fixup and _dl_profile_fixup is checked and we can start using
faster SSE-using functions in parts of ld.so.
There will be more than one function which, in multiarch mode, wants
to use SSSE3. We should not test in each of them for Atoms with
slow SSSE3. Instead, disable the SSSE3 bit in the startup code for
such machines.
Some of the new multi-arch string functions for x86-64 were
not aligned to 16 byte boundarie,s possibly creating unnecessary
cache line misses and delays.
This patch adds SSSE3 strcpy/stpcpy. I got up to 4X speed up on Core 2
and Core i7. I disabled it on Atom since SSSE3 version is slower for
shorter (<64byte) data.
SO far Intel and AMD use exactly the same bits meaning the same
things in CPUID index 1. Simplify the code. Should an architecture
come along which doesn't use the same semantics then it must use a
different index value than COMMON_CPUID_INDEX_1.
