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[PATCH] x86: Use RTM intrinsics in pthread mutex lock elision
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: libc-alpha at sourceware dot org
- Date: Mon, 1 Oct 2018 15:08:31 -0700
- Subject: [PATCH] x86: Use RTM intrinsics in pthread mutex lock elision
Since RTM intrinsics are supported in GCC 4.9, we can use them in
pthread mutex lock elision.
* sysdeps/unix/sysv/linux/x86/Makefile (CFLAGS-elision-lock.c):
Add -mrtm.
(CFLAGS-elision-unlock.c): Likewise.
(CFLAGS-elision-timed.c): Likewise.
(CFLAGS-elision-trylock.c): Likewise.
* sysdeps/unix/sysv/linux/x86/hle.h: Rewritten.
---
sysdeps/unix/sysv/linux/x86/Makefile | 4 ++
sysdeps/unix/sysv/linux/x86/hle.h | 70 ++--------------------------
2 files changed, 7 insertions(+), 67 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index 7dc4e61756..02ca36c6d2 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -14,6 +14,10 @@ endif
ifeq ($(subdir),nptl)
libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \
elision-trylock
+CFLAGS-elision-lock.c += -mrtm
+CFLAGS-elision-unlock.c += -mrtm
+CFLAGS-elision-timed.c += -mrtm
+CFLAGS-elision-trylock.c += -mrtm
endif
ifeq ($(subdir),elf)
diff --git a/sysdeps/unix/sysv/linux/x86/hle.h b/sysdeps/unix/sysv/linux/x86/hle.h
index 4a7b9e3bf7..0449026839 100644
--- a/sysdeps/unix/sysv/linux/x86/hle.h
+++ b/sysdeps/unix/sysv/linux/x86/hle.h
@@ -1,75 +1,11 @@
-/* Shared RTM header. Emulate TSX intrinsics for compilers and assemblers
- that do not support the intrinsics and instructions yet. */
+/* Shared RTM header. */
#ifndef _HLE_H
#define _HLE_H 1
-#ifdef __ASSEMBLER__
+#include <x86intrin.h>
-.macro XBEGIN target
- .byte 0xc7,0xf8
- .long \target-1f
-1:
-.endm
-
-.macro XEND
- .byte 0x0f,0x01,0xd5
-.endm
-
-.macro XABORT code
- .byte 0xc6,0xf8,\code
-.endm
-
-.macro XTEST
- .byte 0x0f,0x01,0xd6
-.endm
-
-#endif
-
-/* Official RTM intrinsics interface matching gcc/icc, but works
- on older gcc compatible compilers and binutils.
- We should somehow detect if the compiler supports it, because
- it may be able to generate slightly better code. */
-
-#define _XBEGIN_STARTED (~0u)
-#define _XABORT_EXPLICIT (1 << 0)
-#define _XABORT_RETRY (1 << 1)
-#define _XABORT_CONFLICT (1 << 2)
-#define _XABORT_CAPACITY (1 << 3)
-#define _XABORT_DEBUG (1 << 4)
-#define _XABORT_NESTED (1 << 5)
-#define _XABORT_CODE(x) (((x) >> 24) & 0xff)
-
-#define _ABORT_LOCK_BUSY 0xff
+#define _ABORT_LOCK_BUSY 0xff
#define _ABORT_LOCK_IS_LOCKED 0xfe
#define _ABORT_NESTED_TRYLOCK 0xfd
-#ifndef __ASSEMBLER__
-
-#define __force_inline __attribute__((__always_inline__)) inline
-
-static __force_inline int _xbegin(void)
-{
- int ret = _XBEGIN_STARTED;
- asm volatile (".byte 0xc7,0xf8 ; .long 0" : "+a" (ret) :: "memory");
- return ret;
-}
-
-static __force_inline void _xend(void)
-{
- asm volatile (".byte 0x0f,0x01,0xd5" ::: "memory");
-}
-
-static __force_inline void _xabort(const unsigned int status)
-{
- asm volatile (".byte 0xc6,0xf8,%P0" :: "i" (status) : "memory");
-}
-
-static __force_inline int _xtest(void)
-{
- unsigned char out;
- asm volatile (".byte 0x0f,0x01,0xd6 ; setnz %0" : "=r" (out) :: "memory");
- return out;
-}
-
-#endif
#endif
--
2.17.1