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| author | Ulrich Drepper <drepper@redhat.com> | 2009-07-17 15:50:23 -0700 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2009-07-17 15:50:23 -0700 |
| commit | 0adae4681750bea9eb729c8935d4b152de4a6b68 (patch) | |
| tree | bca81eae4d40b31cc66782d8f297150290c10cc3 /nptl | |
| parent | c3c2f3cf56ffcfd200f6c26aa5492049140bbbcb (diff) | |
| download | glibc-0adae4681750bea9eb729c8935d4b152de4a6b68.zip glibc-0adae4681750bea9eb729c8935d4b152de4a6b68.tar.gz glibc-0adae4681750bea9eb729c8935d4b152de4a6b68.tar.bz2 | |
Optimize x86-64 sem_wait for uncontested semaphore.
Diffstat (limited to 'nptl')
| -rw-r--r-- | nptl/ChangeLog | 3 | ||||
| -rw-r--r-- | nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S | 51 |
2 files changed, 30 insertions, 24 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog index 5204ad1..5db47a1 100644 --- a/nptl/ChangeLog +++ b/nptl/ChangeLog @@ -1,5 +1,8 @@ 2009-07-17 Ulrich Drepper <drepper@redhat.com> + * sysdeps/unix/sysv/linux/x86_64/sem_wait.S (sem_wait): Optimize + handling of uncontested semaphore. + * sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S (__condvar_cleanup): Rewrite to use cfi directives instead of hand-coded unwind tables. diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S index de6a53b..a01d745 100644 --- a/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S +++ b/nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S @@ -40,18 +40,11 @@ sem_wait: cfi_personality(DW_EH_PE_udata4, __gcc_personality_v0) cfi_lsda(DW_EH_PE_udata4, .LexceptSTART) #endif - pushq %r12 - cfi_adjust_cfa_offset(8) - cfi_rel_offset(%r12, 0) - pushq %r13 - cfi_adjust_cfa_offset(8) - cfi_rel_offset(%r13, 0) - movq %rdi, %r13 #if VALUE == 0 - movl (%r13), %eax + movl (%rdi), %eax #else - movl VALUE(%r13), %eax + movl VALUE(%rdi), %eax #endif 2: testl %eax, %eax je 1f @@ -59,27 +52,24 @@ sem_wait: leal -1(%rax), %edx LOCK #if VALUE == 0 - cmpxchgl %edx, (%r13) + cmpxchgl %edx, (%rdi) #else - cmpxchgl %edx, VALUE(%r13) + cmpxchgl %edx, VALUE(%rdi) #endif jne 2b -7: xorl %eax, %eax - -9: popq %r13 - cfi_adjust_cfa_offset(-8) - cfi_restore(%r13) - popq %r12 - cfi_adjust_cfa_offset(-8) - cfi_restore(%r12) - + xorl %eax, %eax retq - cfi_adjust_cfa_offset(2 * 8) - cfi_rel_offset(%r12, 8) +1: pushq %r12 + cfi_adjust_cfa_offset(8) + cfi_rel_offset(%r12, 0) + pushq %r13 + cfi_adjust_cfa_offset(8) cfi_rel_offset(%r13, 0) -1: LOCK + movq %rdi, %r13 + + LOCK addq $1, NWAITERS(%r13) .LcleanupSTART: @@ -128,8 +118,21 @@ sem_wait: LOCK subq $1, NWAITERS(%r13) - jmp 7b + xorl %eax, %eax + +9: popq %r13 + cfi_adjust_cfa_offset(-8) + cfi_restore(%r13) + popq %r12 + cfi_adjust_cfa_offset(-8) + cfi_restore(%r12) + + retq + + cfi_adjust_cfa_offset(2 * 8) + cfi_rel_offset(%r12, 8) + cfi_rel_offset(%r13, 0) 4: negq %r12 #if USE___THREAD movq errno@gottpoff(%rip), %rdx |