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3 Commits

Author SHA1 Message Date
H.J. Lu
b52b0d793d x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve [BZ #21265] 
In _dl_runtime_resolve, use fxsave/xsave/xsavec to preserve all vector,
mask and bound registers.  It simplifies _dl_runtime_resolve and supports
different calling conventions.  ld.so code size is reduced by more than
1 KB.  However, use fxsave/xsave/xsavec takes a little bit more cycles
than saving and restoring vector and bound registers individually.

Latency for _dl_runtime_resolve to lookup the function, foo, from one
shared library plus libc.so:

                             Before    After     Change

Westmere (SSE)/fxsave         345      866       151%
IvyBridge (AVX)/xsave         420      643       53%
Haswell (AVX)/xsave           713      1252      75%
Skylake (AVX+MPX)/xsavec      559      719       28%
Skylake (AVX512+MPX)/xsavec   145      272       87%
Ryzen (AVX)/xsavec            280      553       97%

This is the worst case where portion of time spent for saving and
restoring registers is bigger than majority of cases.  With smaller
_dl_runtime_resolve code size, overall performance impact is negligible.

On IvyBridge, differences in build and test time of binutils with lazy
binding GCC and binutils are noises.  On Westmere, differences in
bootstrap and "makc check" time of GCC 7 with lazy binding GCC and
binutils are also noises.

	[BZ #21265]
	* sysdeps/x86/cpu-features-offsets.sym (XSAVE_STATE_SIZE_OFFSET):
	New.
	* sysdeps/x86/cpu-features.c: Include <libc-pointer-arith.h>.
	(get_common_indeces): Set xsave_state_size, xsave_state_full_size
	and bit_arch_XSAVEC_Usable if needed.
	(init_cpu_features): Remove bit_arch_Use_dl_runtime_resolve_slow
	and bit_arch_Use_dl_runtime_resolve_opt.
	* sysdeps/x86/cpu-features.h (bit_arch_Use_dl_runtime_resolve_opt):
	Removed.
	(bit_arch_Use_dl_runtime_resolve_slow): Likewise.
	(bit_arch_Prefer_No_AVX512): Updated.
	(bit_arch_MathVec_Prefer_No_AVX512): Likewise.
	(bit_arch_XSAVEC_Usable): New.
	(STATE_SAVE_OFFSET): Likewise.
	(STATE_SAVE_MASK): Likewise.
	[__ASSEMBLER__]: Include <cpu-features-offsets.h>.
	(cpu_features): Add xsave_state_size and xsave_state_full_size.
	(index_arch_Use_dl_runtime_resolve_opt): Removed.
	(index_arch_Use_dl_runtime_resolve_slow): Likewise.
	(index_arch_XSAVEC_Usable): New.
	* sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)):
	Support XSAVEC_Usable.  Remove Use_dl_runtime_resolve_slow.
	* sysdeps/x86_64/Makefile (tst-x86_64-1-ENV): New if tunables
	is enabled.
	* sysdeps/x86_64/dl-machine.h (elf_machine_runtime_setup):
	Replace _dl_runtime_resolve_sse, _dl_runtime_resolve_avx,
	_dl_runtime_resolve_avx_slow, _dl_runtime_resolve_avx_opt,
	_dl_runtime_resolve_avx512 and _dl_runtime_resolve_avx512_opt
	with _dl_runtime_resolve_fxsave, _dl_runtime_resolve_xsave and
	_dl_runtime_resolve_xsavec.
	* sysdeps/x86_64/dl-trampoline.S (DL_RUNTIME_UNALIGNED_VEC_SIZE):
	Removed.
	(DL_RUNTIME_RESOLVE_REALIGN_STACK): Check STATE_SAVE_ALIGNMENT
	instead of VEC_SIZE.
	(REGISTER_SAVE_BND0): Removed.
	(REGISTER_SAVE_BND1): Likewise.
	(REGISTER_SAVE_BND3): Likewise.
	(REGISTER_SAVE_RAX): Always defined to 0.
	(VMOV): Removed.
	(_dl_runtime_resolve_avx): Likewise.
	(_dl_runtime_resolve_avx_slow): Likewise.
	(_dl_runtime_resolve_avx_opt): Likewise.
	(_dl_runtime_resolve_avx512): Likewise.
	(_dl_runtime_resolve_avx512_opt): Likewise.
	(_dl_runtime_resolve_sse): Likewise.
	(_dl_runtime_resolve_sse_vex): Likewise.
	(USE_FXSAVE): New.
	(_dl_runtime_resolve_fxsave): Likewise.
	(USE_XSAVE): Likewise.
	(_dl_runtime_resolve_xsave): Likewise.
	(USE_XSAVEC): Likewise.
	(_dl_runtime_resolve_xsavec): Likewise.
	* sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve_avx512):
	Removed.
	(_dl_runtime_resolve_avx512_opt): Likewise.
	(_dl_runtime_resolve_avx): Likewise.
	(_dl_runtime_resolve_avx_opt): Likewise.
	(_dl_runtime_resolve_sse): Likewise.
	(_dl_runtime_resolve_sse_vex): Likewise.
	(_dl_runtime_resolve_fxsave): New.
	(_dl_runtime_resolve_xsave): Likewise.
	(_dl_runtime_resolve_xsavec): Likewise.
 2017-10-20 11:00:34 -07:00
H.J. Lu
2a1f15b1a9 Remove x86 ifunc-defines.sym and rtld-global-offsets.sym 
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>.
 2016-05-11 05:51:39 -07:00
H.J. Lu
e2e4f56056 Add _dl_x86_cpu_features to rtld_global 
This patch adds _dl_x86_cpu_features to rtld_global in x86 ld.so
and initializes it early before __libc_start_main is called so that
cpu_features is always available when it is used and we can avoid
calling __init_cpu_features in IFUNC selectors.

	* sysdeps/i386/dl-machine.h: Include <cpu-features.c>.
	(dl_platform_init): Call init_cpu_features.
	* sysdeps/i386/dl-procinfo.c (_dl_x86_cpu_features): New.
	* sysdeps/i386/i686/cacheinfo.c
	(DISABLE_PREFERRED_MEMORY_INSTRUCTION): Removed.
	* sysdeps/i386/i686/multiarch/Makefile (aux): Remove init-arch.
	* sysdeps/i386/i686/multiarch/Versions: Removed.
	* sysdeps/i386/i686/multiarch/ifunc-defines.sym (KIND_OFFSET):
	Removed.
	* sysdeps/i386/ldsodefs.h: Include <cpu-features.h>.
	* sysdeps/unix/sysv/linux/x86/Makefile
	(libpthread-sysdep_routines): Remove init-arch.
	* sysdeps/unix/sysv/linux/x86_64/dl-procinfo.c: Include
	<sysdeps/x86_64/dl-procinfo.c> instead of
	sysdeps/generic/dl-procinfo.c>.
	* sysdeps/x86/Makefile [$(subdir) == csu] (gen-as-const-headers):
	Add cpu-features-offsets.sym and rtld-global-offsets.sym.
	[$(subdir) == elf] (sysdep-dl-routines): Add dl-get-cpu-features.
	[$(subdir) == elf] (tests): Add tst-get-cpu-features.
	[$(subdir) == elf] (tests-static): Add
	tst-get-cpu-features-static.
	* sysdeps/x86/Versions: New file.
	* sysdeps/x86/cpu-features-offsets.sym: Likewise.
	* sysdeps/x86/cpu-features.c: Likewise.
	* sysdeps/x86/cpu-features.h: Likewise.
	* sysdeps/x86/dl-get-cpu-features.c: Likewise.
	* sysdeps/x86/libc-start.c: Likewise.
	* sysdeps/x86/rtld-global-offsets.sym: Likewise.
	* sysdeps/x86/tst-get-cpu-features-static.c: Likewise.
	* sysdeps/x86/tst-get-cpu-features.c: Likewise.
	* sysdeps/x86_64/dl-procinfo.c: Likewise.
	* sysdeps/x86_64/cacheinfo.c (__cpuid_count): Removed.
	Assume USE_MULTIARCH is defined and don't check it.
	(is_intel): Replace __cpu_features with GLRO(dl_x86_cpu_features).
	(is_amd): Likewise.
	(max_cpuid): Likewise.
	(intel_check_word): Likewise.
	(__cache_sysconf): Don't call __init_cpu_features.
	(__x86_preferred_memory_instruction): Removed.
	(init_cacheinfo): Don't call __init_cpu_features. Replace
	__cpu_features with GLRO(dl_x86_cpu_features).
	* sysdeps/x86_64/dl-machine.h: <cpu-features.c>.
	(dl_platform_init): Call init_cpu_features.
	* sysdeps/x86_64/ldsodefs.h: Include <cpu-features.h>.
	* sysdeps/x86_64/multiarch/Makefile (aux): Remove init-arch.
	* sysdeps/x86_64/multiarch/Versions: Removed.
	* sysdeps/x86_64/multiarch/cacheinfo.c: Likewise.
	* sysdeps/x86_64/multiarch/init-arch.c: Likewise.
	* sysdeps/x86_64/multiarch/ifunc-defines.sym (KIND_OFFSET):
	Removed.
	* sysdeps/x86_64/multiarch/init-arch.h: Rewrite.
 2015-08-13 03:41:22 -07:00