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authorUlrich Drepper <drepper@redhat.com>2009-08-08 10:21:46 -0700
committerUlrich Drepper <drepper@redhat.com>2009-08-08 10:21:46 -0700
commit49eea97b00d367aa3eac3dfd047c259e7bd04732 (patch)
tree689337823f6e88b1c410dfcd1dbc12f6d4a5f63f /nptl
parent8e436522e108229eeb96d8921c659c5a19eaf455 (diff)
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Another minor optimization of x86-64 pthread_cond_wait.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/ChangeLog6
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S22
2 files changed, 13 insertions, 15 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 0f5c231..48fcc0f 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,9 @@
+2009-08-08 Ulrich Drepper <drepper@redhat.com>
+
+ * sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
+ (__pthread_cond_wait): Optimize by avoiding use of callee-safe
+ register.
+
2009-08-07 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/sysv/linux/x86_64/sem_wait.S: Little optimizations
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
index 45116b1..f5b929e 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
@@ -45,9 +45,6 @@ __pthread_cond_wait:
cfi_lsda(DW_EH_PE_udata4, .LexceptSTART)
#endif
- pushq %r13
- cfi_adjust_cfa_offset(8)
- cfi_rel_offset(%r13, 0)
#define FRAME_SIZE 32
leaq -FRAME_SIZE(%rsp), %rsp
cfi_adjust_cfa_offset(FRAME_SIZE)
@@ -140,7 +137,7 @@ __pthread_cond_wait:
movl $SYS_futex, %eax
syscall
- movl $1, %r13d
+ movl $1, %r8d
#ifdef __ASSUME_REQUEUE_PI
jmp 62f
#else
@@ -158,7 +155,7 @@ __pthread_cond_wait:
#else
orl %fs:PRIVATE_FUTEX, %esi
#endif
-60: xorl %r13d, %r13d
+60: xorl %r8d, %r8d
movl $SYS_futex, %eax
syscall
@@ -233,20 +230,18 @@ __pthread_cond_wait:
/* If requeue_pi is used the kernel performs the locking of the
mutex. */
11: movq 16(%rsp), %rdi
- testl %r13d, %r13d
+ testl %r8d, %r8d
jnz 18f
callq __pthread_mutex_cond_lock
-14: movq FRAME_SIZE(%rsp), %r13
- leaq FRAME_SIZE+8(%rsp), %rsp
- cfi_adjust_cfa_offset(-(FRAME_SIZE + 8))
+14: leaq FRAME_SIZE(%rsp), %rsp
+ cfi_adjust_cfa_offset(-FRAME_SIZE)
/* We return the result of the mutex_lock operation. */
retq
- cfi_adjust_cfa_offset(8 + FRAME_SIZE)
- cfi_rel_offset(%r13, FRAME_SIZE)
+ cfi_adjust_cfa_offset(FRAME_SIZE)
18: callq __pthread_mutex_cond_lock_adjust
xorl %eax, %eax
@@ -341,9 +336,7 @@ versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
__condvar_cleanup1:
/* Stack frame:
- rsp + 40
- +--------------------------+
- rsp + 32 | %r13 |
+ rsp + 32
+--------------------------+
rsp + 24 | unused |
+--------------------------+
@@ -465,7 +458,6 @@ __condvar_cleanup1:
callq __pthread_mutex_cond_lock
movq 24(%rsp), %rdi
- movq 32(%rsp), %r13
.LcallUR:
call _Unwind_Resume@PLT
hlt