MEDIUM: listener: add support for linux's accept4() syscall
On Linux, accept4() does the same as accept() except that it allows
the caller to specify some flags to set on the resulting socket. We
use this to set the O_NONBLOCK flag and thus to save one fcntl()
call in each connection. The effect is a small performance gain of
around 1%.
The option is automatically enabled when target linux2628 is set, or
when the USE_ACCEPT4 Makefile variable is set. If the libc is too old
to provide the equivalent function, this is automatically detected and
our own function is used instead. In any case it is possible to force
the use of our implementation with USE_MY_ACCEPT4.
diff --git a/Makefile b/Makefile
index 653c083..5652d59 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,8 @@
# USE_GETADDRINFO : use getaddrinfo() to resolve IPv6 host names.
# USE_OPENSSL : enable use of OpenSSL. Recommended, but see below.
# USE_FUTEX : enable use of futex on kernel 2.6. Automatic.
+# USE_ACCEPT4 : enable use of accept4() on linux. Automatic.
+# USE_MY_ACCEPT4 : use own implemention of accept4() if glibc < 2.10.
#
# Options can be forced by specifying "USE_xxx=1" or can be disabled by using
# "USE_xxx=" (empty string).
@@ -240,6 +242,7 @@
USE_LIBCRYPT = implicit
USE_LINUX_SPLICE= implicit
USE_LINUX_TPROXY= implicit
+ USE_ACCEPT4 = implicit
USE_FUTEX = implicit
else
ifeq ($(TARGET),solaris)
@@ -439,6 +442,16 @@
BUILD_OPTIONS += $(call ignore_implicit,USE_MY_SPLICE)
endif
+ifneq ($(USE_ACCEPT4),)
+OPTIONS_CFLAGS += -DUSE_ACCEPT4
+BUILD_OPTIONS += $(call ignore_implicit,USE_ACCEPT4)
+endif
+
+ifneq ($(USE_MY_ACCEPT4),)
+OPTIONS_CFLAGS += -DUSE_MY_ACCEPT4
+BUILD_OPTIONS += $(call ignore_implicit,USE_MY_ACCEPT4)
+endif
+
ifneq ($(USE_NETFILTER),)
OPTIONS_CFLAGS += -DNETFILTER
BUILD_OPTIONS += $(call ignore_implicit,USE_NETFILTER)