Avoid a system call in 'gettid'.
System calls can be pretty slow. This is mako, which has one of our
lowest latencies:
iterations ns/op
BM_unistd_getpid 10000000 209
BM_unistd_gettid 200000000 8
Bug: 15297299 (kernel panic from too many gettid calls)
Bug: 15315766 (excessive gettid overhead in liblogd)
Change-Id: I49656c0fc5b5d092390264a59e4f2c0d8a8b1aeb
diff --git a/benchmarks/unistd_benchmark.cpp b/benchmarks/unistd_benchmark.cpp
index e839bf8..12b788a 100644
--- a/benchmarks/unistd_benchmark.cpp
+++ b/benchmarks/unistd_benchmark.cpp
@@ -28,3 +28,14 @@
StopBenchmarkTiming();
}
BENCHMARK(BM_unistd_getpid);
+
+static void BM_unistd_gettid(int iters) {
+ StartBenchmarkTiming();
+
+ for (int i = 0; i < iters; ++i) {
+ gettid();
+ }
+
+ StopBenchmarkTiming();
+}
+BENCHMARK(BM_unistd_gettid);
diff --git a/libc/Android.mk b/libc/Android.mk
index c573e30..4783bd3 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -128,6 +128,7 @@
bionic/getauxval.cpp \
bionic/getcwd.cpp \
bionic/getpgrp.cpp \
+ bionic/gettid.cpp \
bionic/inotify_init.cpp \
bionic/lchown.cpp \
bionic/lfs64_support.cpp \
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 785d191..584c1ae 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -38,7 +38,6 @@
uid_t getresuid:getresuid(uid_t* ruid, uid_t* euid, uid_t* suid) arm64,mips,mips64,x86_64
gid_t getresgid:getresgid32(gid_t* rgid, gid_t* egid, gid_t* sgid) arm,x86
gid_t getresgid:getresgid(gid_t* rgid, gid_t* egid, gid_t* sgid) arm64,mips,mips64,x86_64
-pid_t gettid() all
ssize_t readahead(int, off64_t, size_t) all
int getgroups:getgroups32(int, gid_t*) arm,x86
int getgroups:getgroups(int, gid_t*) arm64,mips,mips64,x86_64
diff --git a/libc/arch-arm/syscalls/gettid.S b/libc/arch-arm/syscalls/gettid.S
deleted file mode 100644
index 3928be1..0000000
--- a/libc/arch-arm/syscalls/gettid.S
+++ /dev/null
@@ -1,14 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- mov ip, r7
- ldr r7, =__NR_gettid
- swi #0
- mov r7, ip
- cmn r0, #(MAX_ERRNO + 1)
- bxls lr
- neg r0, r0
- b __set_errno
-END(gettid)
diff --git a/libc/arch-arm64/syscalls/gettid.S b/libc/arch-arm64/syscalls/gettid.S
deleted file mode 100644
index 44ca913..0000000
--- a/libc/arch-arm64/syscalls/gettid.S
+++ /dev/null
@@ -1,25 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- stp x29, x30, [sp, #-16]!
- .cfi_def_cfa_offset 16
- .cfi_rel_offset x29, 0
- .cfi_rel_offset x30, 8
- mov x29, sp
-
- mov x8, __NR_gettid
- svc #0
-
- ldp x29, x30, [sp], #16
- .cfi_def_cfa_offset 0
- .cfi_restore x29
- .cfi_restore x30
-
- cmn x0, #(MAX_ERRNO + 1)
- cneg x0, x0, hi
- b.hi __set_errno
-
- ret
-END(gettid)
diff --git a/libc/arch-mips/syscalls/gettid.S b/libc/arch-mips/syscalls/gettid.S
deleted file mode 100644
index cfdc57b..0000000
--- a/libc/arch-mips/syscalls/gettid.S
+++ /dev/null
@@ -1,19 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- .set noreorder
- .cpload t9
- li v0, __NR_gettid
- syscall
- bnez a3, 1f
- move a0, v0
- j ra
- nop
-1:
- la t9,__set_errno
- j t9
- nop
- .set reorder
-END(gettid)
diff --git a/libc/arch-mips64/syscalls/gettid.S b/libc/arch-mips64/syscalls/gettid.S
deleted file mode 100644
index 30c30c8..0000000
--- a/libc/arch-mips64/syscalls/gettid.S
+++ /dev/null
@@ -1,25 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- .set push
- .set noreorder
- li v0, __NR_gettid
- syscall
- bnez a3, 1f
- move a0, v0
- j ra
- nop
-1:
- move t0, ra
- bal 2f
- nop
-2:
- .cpsetup ra, t1, 2b
- LA t9,__set_errno
- .cpreturn
- j t9
- move ra, t0
- .set pop
-END(gettid)
diff --git a/libc/arch-x86/syscalls/gettid.S b/libc/arch-x86/syscalls/gettid.S
deleted file mode 100644
index 1f264b1..0000000
--- a/libc/arch-x86/syscalls/gettid.S
+++ /dev/null
@@ -1,17 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- movl $__NR_gettid, %eax
- int $0x80
- cmpl $-MAX_ERRNO, %eax
- jb 1f
- negl %eax
- pushl %eax
- call __set_errno
- addl $4, %esp
- orl $-1, %eax
-1:
- ret
-END(gettid)
diff --git a/libc/arch-x86_64/syscalls/gettid.S b/libc/arch-x86_64/syscalls/gettid.S
deleted file mode 100644
index 65ecc16..0000000
--- a/libc/arch-x86_64/syscalls/gettid.S
+++ /dev/null
@@ -1,16 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(gettid)
- movl $__NR_gettid, %eax
- syscall
- cmpq $-MAX_ERRNO, %rax
- jb 1f
- negl %eax
- movl %eax, %edi
- call __set_errno
- orq $-1, %rax
-1:
- ret
-END(gettid)
diff --git a/libc/bionic/gettid.cpp b/libc/bionic/gettid.cpp
new file mode 100644
index 0000000..f42e36a
--- /dev/null
+++ b/libc/bionic/gettid.cpp
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <unistd.h>
+
+#include "pthread_internal.h"
+
+pid_t gettid() {
+ return __get_thread()->tid;
+}