lib: Substitute poll APIs with epoll APIs in thread management routine

This commit substitutes poll APIs with epoll APIs for better performace. Note that epoll APIs are only available for Linux. For BSD platforms which do not support epoll APIs, poll APIs are still used.

Signed-off-by: Kaifei Peng <[email protected]>

configure.ac

@@ -1496,6 +1496,26 @@ AC_CHECK_FUNCS([pollts], [
   AC_DEFINE([HAVE_POLLTS], [1], [have NetBSD pollts()])
 ])
 
+AC_ARG_ENABLE([epoll],
+  [AS_HELP_STRING([--enable-epoll], [Enable epoll support])],
+  [enable_epoll=yes],
+  [enable_epoll=no])
+
+if test "x$enable_epoll" = "xyes"; then
+    AC_CHECK_FUNC([epoll_wait], [AC_DEFINE([HAVE_EPOLL_WAIT], [1], [Define if you have epoll_wait])])
+    AC_CHECK_FUNC([epoll_pwait], [AC_DEFINE([HAVE_EPOLL_PWAIT], [1], [Define if you have epoll_pwait])])
+    AC_CHECK_FUNC([epoll_pwait2], [AC_DEFINE([HAVE_EPOLL_PWAIT2], [1], [Define if you have epoll_pwait2])])
+
+    # Define USE_EPOLL if any of the above is found
+    AC_MSG_CHECKING([for any epoll API support])
+    if test "x$ac_cv_func_epoll_wait" = "xyes" || test "x$ac_cv_func_epoll_pwait" = "xyes" || test "x$ac_cv_func_epoll_pwait2" = "xyes"; then
+        AC_DEFINE([USE_EPOLL], [1], [Define if any epoll API is supported])
+        AC_MSG_RESULT([yes])
+    else
+        AC_MSG_RESULT([no])
+    fi
+fi
+
 AC_CHECK_HEADER([asm-generic/unistd.h],
                 [AC_CHECK_DECL(__NR_setns,
                                AC_DEFINE([HAVE_NETNS], [1], [Have netns]),,