From 973eaedf51a8ab0f9881c1fb900850dd8475bbf7 Mon Sep 17 00:00:00 2001
From: "Carsten Haitzler (Rasterman)" <raster@rasterman.com>
Date: Fri, 28 Oct 2016 14:50:05 +0900
Subject: [PATCH] improve responsivness of timer sleeping threads for vsync
 with prctl

prctl allows us on some platforms to request a thread be woken up more
agressively e.g. due to a timeout bu setting timerslack. since we use
a dedicated thread just for vsync events, this is a very good idea to
ask the kernel to be as exact as possible for this thread as it only
wakes up once per frame (or should only) and accuracy is important. so
use this.

also improve prctl checks to be more explicit in configure.ac and use
these ifdefs in ecore exe too where prctl is used as well.

@feature
---
 configure.ac                         |  2 +-
 m4/efl_check_funcs.m4                | 11 +++++++++++
 src/lib/ecore/ecore_anim.c           |  7 +++++++
 src/lib/ecore/ecore_exe_posix.c      | 10 +++++-----
 src/lib/ecore_x/xlib/ecore_x_vsync.c |  7 +++++++
 5 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index 1a850808f8..4e61cc5d40 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1029,7 +1029,7 @@ EFL_CHECK_GCC_BUILTIN([bswap64], [HAVE_BSWAP64])
 
 AC_CHECK_FUNCS([fchmod])
 
-EFL_CHECK_FUNCS([EINA], [dlopen dladdr iconv shm_open splice setxattr getpagesize])
+EFL_CHECK_FUNCS([EINA], [dlopen dladdr iconv shm_open splice setxattr getpagesize prctl])
 
 enable_log="no"
 if test "x${efl_func_fnmatch}" = "xyes" && test "x${want_log}" = "xyes" ; then
diff --git a/m4/efl_check_funcs.m4 b/m4/efl_check_funcs.m4
index 39fb5ee5ad..b44f20bc55 100644
--- a/m4/efl_check_funcs.m4
+++ b/m4/efl_check_funcs.m4
@@ -288,6 +288,17 @@ sz = getpagesize();
 ]])
 ])
 
+dnl _EFL_CHECK_FUNC_PRCTL is for internal use
+dnl _EFL_CHECK_FUNC_PRCTL(EFL, VARIABLE)
+AC_DEFUN([_EFL_CHECK_FUNC_PRCTL],
+[EFL_FIND_LIB_FOR_CODE([$1], [], [$2], [[
+#include <sys/prctl.h>
+]],
+[[
+prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
+]])
+])
+
 dnl Macro that checks function availability
 dnl
 dnl EFL_CHECK_FUNC(EFL, FUNCTION)
diff --git a/src/lib/ecore/ecore_anim.c b/src/lib/ecore/ecore_anim.c
index c069c96118..66432868d5 100644
--- a/src/lib/ecore/ecore_anim.c
+++ b/src/lib/ecore/ecore_anim.c
@@ -30,6 +30,10 @@
 
 #endif /* ! _WIN32 */
 
+#ifdef HAVE_PRCTL
+# include <sys/prctl.h>
+#endif
+
 #include "Ecore.h"
 #include "ecore_private.h"
 
@@ -109,6 +113,9 @@ _timer_tick_core(void *data EINA_UNUSED, Ecore_Thread *thread)
    int ret;
 
    eina_thread_name_set(eina_thread_self(), "Eanimator-timer");
+#ifdef HAVE_PRCTL
+   prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
+#endif
    while (!ecore_thread_check(thread))
      {
         DBG("------- timer_event_is_busy=%i", timer_event_is_busy);
diff --git a/src/lib/ecore/ecore_exe_posix.c b/src/lib/ecore/ecore_exe_posix.c
index 5ad60f9010..14c7d6963f 100644
--- a/src/lib/ecore/ecore_exe_posix.c
+++ b/src/lib/ecore/ecore_exe_posix.c
@@ -13,7 +13,7 @@
 #include <sys/time.h>
 #include <sys/resource.h>
 
-#ifdef HAVE_SYS_PRCTL_H
+#ifdef HAVE_PRCTL
 # include <sys/prctl.h>
 #endif
 
@@ -1017,11 +1017,11 @@ _ecore_exe_exec_it(const char     *exe_cmd,
       }
    }
 
-#ifdef HAVE_SYS_PRCTL_H
+#ifdef HAVE_PRCTL
    if ((flags & ECORE_EXE_TERM_WITH_PARENT))
-   {
-      prctl(PR_SET_PDEATHSIG, SIGTERM);
-   }
+     {
+        prctl(PR_SET_PDEATHSIG, SIGTERM);
+     }
 #endif
 
    if (!(flags & ECORE_EXE_NOT_LEADER)) setsid();
diff --git a/src/lib/ecore_x/xlib/ecore_x_vsync.c b/src/lib/ecore_x/xlib/ecore_x_vsync.c
index 436645e63c..ee43406ab5 100644
--- a/src/lib/ecore_x/xlib/ecore_x_vsync.c
+++ b/src/lib/ecore_x/xlib/ecore_x_vsync.c
@@ -17,6 +17,10 @@
 #include <sys/select.h>
 #include <fcntl.h>
 
+#ifdef HAVE_PRCTL
+# include <sys/prctl.h>
+#endif
+
 #define ECORE_X_VSYNC_DRM 1
 
 static Ecore_X_Window vsync_root = 0;
@@ -286,6 +290,9 @@ _drm_tick_core(void *data EINA_UNUSED, Ecore_Thread *thread)
    int tick = 0;
 
    eina_thread_name_set(eina_thread_self(), "Eanimator-vsync");
+#ifdef HAVE_PRCTL
+   prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0);
+#endif
    while (!ecore_thread_check(thread))
      {
         DBG("------- drm_event_is_busy=%i", drm_event_is_busy);