runtime: change GNU/Linux usleep to use nanosleep

Ever since we added sleep to the runtime back in 2008, we've
implemented it on GNU/Linux with the select (or pselect or pselect6)
system call. But the Linux kernel has a nanosleep system call,
which should be a tiny bit more efficient since it doesn't have to
check to see whether there are any file descriptors. So use it.

Change-Id: Icc3430baca46b082a4d33f97c6c47e25fa91cb9a
Reviewed-on: https://go-review.googlesource.com/108538
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
index 721551faec0e7cd383b7316f99160b7b78029573..8d5a4ff9772d2171940dfb0cc2a07808f4188670 100644 (file)
--- a/src/runtime/sys_linux_386.s
+++ b/src/runtime/sys_linux_386.s
@@ -39,6 +39,7 @@
 #define SYS_setittimer         104
 #define SYS_clone              120
 #define SYS_sched_yield        158
+#define SYS_nanosleep          162
 #define SYS_rt_sigreturn       173
 #define SYS_rt_sigaction       174
 #define SYS_rt_sigprocmask     175
@@ -56,7 +57,6 @@
 #define SYS_epoll_ctl          255
 #define SYS_epoll_wait         256
 #define SYS_clock_gettime      265
-#define SYS_pselect6           308
 #define SYS_epoll_create1      329
 
 TEXT runtime·exit(SB),NOSPLIT,$0
@@ -141,14 +141,10 @@ TEXT runtime·usleep(SB),NOSPLIT,$8
        MULL    DX
        MOVL    AX, 4(SP)
 
-       // pselect6(0, 0, 0, 0, &ts, 0)
-       MOVL    $SYS_pselect6, AX
-       MOVL    $0, BX
+       // nanosleep(&ts, 0)
+       MOVL    $SYS_nanosleep, AX
+       LEAL    0(SP), BX
        MOVL    $0, CX
-       MOVL    $0, DX
-       MOVL    $0, SI
-       LEAL    0(SP), DI
-       MOVL    $0, BP
        INVOKE_SYSCALL
        RET
 

diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index e03f7ce44c594adbc1c82791a47fb7794086fa89..62d80247bea525f6dd89986a419be5a24f211040 100644 (file)
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -24,6 +24,7 @@
 #define SYS_sched_yield        24
 #define SYS_mincore            27
 #define SYS_madvise            28
+#define SYS_nanosleep          35
 #define SYS_setittimer         38
 #define SYS_getpid             39
 #define SYS_socket             41
@@ -43,7 +44,6 @@
 #define SYS_epoll_ctl          233
 #define SYS_openat             257
 #define SYS_faccessat          269
-#define SYS_pselect6           270
 #define SYS_epoll_pwait                281
 #define SYS_epoll_create1      291
 
@@ -123,14 +123,10 @@ TEXT runtime·usleep(SB),NOSPLIT,$16
        MULL    DX
        MOVQ    AX, 8(SP)
 
-       // pselect6(0, 0, 0, 0, &ts, 0)
-       MOVL    $0, DI
+       // nanosleep(&ts, 0)
+       MOVQ    SP, DI
        MOVL    $0, SI
-       MOVL    $0, DX
-       MOVL    $0, R10
-       MOVQ    SP, R8
-       MOVL    $0, R9
-       MOVL    $SYS_pselect6, AX
+       MOVL    $SYS_nanosleep, AX
        SYSCALL
        RET
 

diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 4dd773adce016bda8b487f78ddd08161a61f00ff..fc9dc9bbb8f51beabfa9a00bdfb21f6b7ef73927 100644 (file)
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -38,7 +38,7 @@
 #define SYS_gettid (SYS_BASE + 224)
 #define SYS_tkill (SYS_BASE + 238)
 #define SYS_sched_yield (SYS_BASE + 158)
-#define SYS_pselect6 (SYS_BASE + 335)
+#define SYS_nanosleep (SYS_BASE + 162)
 #define SYS_sched_getaffinity (SYS_BASE + 242)
 #define SYS_clock_gettime (SYS_BASE + 263)
 #define SYS_epoll_create (SYS_BASE + 250)
@@ -475,13 +475,9 @@ TEXT runtime·usleep(SB),NOSPLIT,$12
        MOVW    $1000, R0       // usec to nsec
        MUL     R0, R1
        MOVW    R1, 8(R13)
-       MOVW    $0, R0
+       MOVW    $4(R13), R0
        MOVW    $0, R1
-       MOVW    $0, R2
-       MOVW    $0, R3
-       MOVW    $4(R13), R4
-       MOVW    $0, R5
-       MOVW    $SYS_pselect6, R7
+       MOVW    $SYS_nanosleep, R7
        SWI     $0
        RET
 

diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
index 8a56ba6babeb459f4ee9ab8f3c8a89b3f5b903b0..f930d1f044ed8be53fa4f90f0a02b22d3d250105 100644 (file)
--- a/src/runtime/sys_linux_arm64.s
+++ b/src/runtime/sys_linux_arm64.s
@@ -21,7 +21,7 @@
 #define SYS_openat             56
 #define SYS_close              57
 #define SYS_fcntl              25
-#define SYS_pselect6           72
+#define SYS_nanosleep          101
 #define SYS_mmap               222
 #define SYS_munmap             215
 #define SYS_setitimer          103
@@ -129,14 +129,10 @@ TEXT runtime·usleep(SB),NOSPLIT,$24-4
        MUL     R4, R5
        MOVD    R5, 16(RSP)
 
-       // pselect6(0, 0, 0, 0, &ts, 0)
-       MOVD    $0, R0
-       MOVD    R0, R1
-       MOVD    R0, R2
-       MOVD    R0, R3
-       ADD     $8, RSP, R4
-       MOVD    R0, R5
-       MOVD    $SYS_pselect6, R8
+       // nanosleep(&ts, 0)
+       ADD     $8, RSP, R0
+       MOVD    $0, R1
+       MOVD    $SYS_nanosleep, R8
        SVC
        RET
 

diff --git a/src/runtime/sys_linux_mips64x.s b/src/runtime/sys_linux_mips64x.s
index 25d13367ad52262c1f06d7f78adb089e387f2b60..7632e06fbd39b618185979b8705d4477c5c95baf 100644 (file)
--- a/src/runtime/sys_linux_mips64x.s
+++ b/src/runtime/sys_linux_mips64x.s
@@ -26,7 +26,7 @@
 #define SYS_munmap             5011
 #define SYS_setitimer          5036
 #define SYS_clone              5055
-#define SYS_newselect          5022
+#define SYS_nanosleep          5034
 #define SYS_sched_yield                5023
 #define SYS_rt_sigreturn       5211
 #define SYS_rt_sigaction       5013
@@ -117,18 +117,16 @@ TEXT runtime·usleep(SB),NOSPLIT,$16-4
        DIVVU   R4, R3
        MOVV    LO, R3
        MOVV    R3, 8(R29)
+       MOVW    $1000, R4
        MULVU   R3, R4
        MOVV    LO, R4
        SUBVU   R4, R5
        MOVV    R5, 16(R29)
 
-       // select(0, 0, 0, 0, &tv)
-       MOVW    $0, R4
+       // nanosleep(&ts, 0)
+       ADDV    $8, R29, R4
        MOVW    $0, R5
-       MOVW    $0, R6
-       MOVW    $0, R7
-       ADDV    $8, R29, R8
-       MOVV    $SYS_newselect, R2
+       MOVV    $SYS_nanosleep, R2
        SYSCALL
        RET
 

diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
index fb6130ac3ae11c93883a58e23fbf9d06944d9a0e..52eccca0931bf07896a74dbdec96115c285f8d84 100644 (file)
--- a/src/runtime/sys_linux_mipsx.s
+++ b/src/runtime/sys_linux_mipsx.s
@@ -26,8 +26,8 @@
 #define SYS_munmap             4091
 #define SYS_setitimer          4104
 #define SYS_clone              4120
-#define SYS_newselect          4142
 #define SYS_sched_yield                4162
+#define SYS_nanosleep          4166
 #define SYS_rt_sigreturn       4193
 #define SYS_rt_sigaction       4194
 #define SYS_rt_sigprocmask     4195
@@ -115,19 +115,16 @@ TEXT runtime·usleep(SB),NOSPLIT,$28-4
        DIVU    R4, R3
        MOVW    LO, R3
        MOVW    R3, 24(R29)
+       MOVW    $1000, R4
        MULU    R3, R4
        MOVW    LO, R4
        SUBU    R4, R5
        MOVW    R5, 28(R29)
 
-       // select(0, 0, 0, 0, &tv)
-       MOVW    $0, R4
+       // nanosleep(&ts, 0)
+       ADDU    $24, R29, R4
        MOVW    $0, R5
-       MOVW    $0, R6
-       MOVW    $0, R7
-       ADDU    $24, R29, R8
-       MOVW    R8, 16(R29)
-       MOVW    $SYS_newselect, R2
+       MOVW    $SYS_nanosleep, R2
        SYSCALL
        RET
 

diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index 77ddf532865c8bba0eb43ecc6f7dea086f300a39..b8fe5cc31bf811c62ade16c37d30b469af465e5b 100644 (file)
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -27,8 +27,8 @@
 #define SYS_munmap              91
 #define SYS_setitimer          104
 #define SYS_clone              120
-#define SYS_newselect          142
 #define SYS_sched_yield                158
+#define SYS_nanosleep          162
 #define SYS_rt_sigreturn       172
 #define SYS_rt_sigaction       173
 #define SYS_rt_sigprocmask     174
@@ -106,17 +106,15 @@ TEXT runtime·usleep(SB),NOSPLIT,$16-4
        MOVW    $1000000, R4
        DIVD    R4, R3
        MOVD    R3, 8(R1)
+       MOVW    $1000, R4
        MULLD   R3, R4
        SUB     R4, R5
        MOVD    R5, 16(R1)
 
-       // select(0, 0, 0, 0, &tv)
-       MOVW    $0, R3
+       // nanosleep(&ts, 0)
+       ADD     $8, R1, R3
        MOVW    $0, R4
-       MOVW    $0, R5
-       MOVW    $0, R6
-       ADD     $8, R1, R7
-       SYSCALL $SYS_newselect
+       SYSCALL $SYS_nanosleep
        RET
 
 TEXT runtime·gettid(SB),NOSPLIT,$0-4

diff --git a/src/runtime/sys_linux_s390x.s b/src/runtime/sys_linux_s390x.s
index 8dbca6cb484c6f001c4681db228123baf7542d81..1ff110c232b87266669d08f76c8d5607381df4cc 100644 (file)
--- a/src/runtime/sys_linux_s390x.s
+++ b/src/runtime/sys_linux_s390x.s
@@ -22,8 +22,8 @@
 #define SYS_munmap               91
 #define SYS_setitimer           104
 #define SYS_clone               120
-#define SYS_select              142
 #define SYS_sched_yield         158
+#define SYS_nanosleep           162
 #define SYS_rt_sigreturn        173
 #define SYS_rt_sigaction        174
 #define SYS_rt_sigprocmask      175
@@ -110,17 +110,15 @@ TEXT runtime·usleep(SB),NOSPLIT,$16-4
        MOVW    $1000000, R3
        DIVD    R3, R2
        MOVD    R2, 8(R15)
+       MOVW    $1000, R3
        MULLD   R2, R3
        SUB     R3, R4
        MOVD    R4, 16(R15)
 
-       // select(0, 0, 0, 0, &tv)
-       MOVW    $0, R2
+       // nanosleep(&ts, 0)
+       ADD     $8, R15, R2
        MOVW    $0, R3
-       MOVW    $0, R4
-       MOVW    $0, R5
-       ADD     $8, R15, R6
-       MOVW    $SYS_select, R1
+       MOVW    $SYS_nanosleep, R1
        SYSCALL
        RET