Enable tpause Exponential backoff and thread delay

diff --git a/include/localfn.h b/include/localfn.h
new file mode 100644
index 00000000000..998e6554aec
--- /dev/null
+++ b/include/localfn.h
@@ -0,0 +1,6 @@ 
+#define RUNLOCALFN(a, b, c)  \
+  do \
+    { \
+      a (b); \
+    } \
+  while (0)
diff --git a/libgomp/config/linux/spin.h b/libgomp/config/linux/spin.h
new file mode 100644
index 00000000000..ad8eba275ed
--- /dev/null
+++ b/libgomp/config/linux/spin.h
@@ -0,0 +1,12 @@ 
+static inline int
+do_spin_for_count (int *addr, int val, unsigned long long count)
+{
+  unsigned long long i;
+  for (i = 0; i < count; i++)
+    if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val, 0))
+      return 0;
+    else
+      cpu_relax ();
+  return 1;
+}
+
diff --git a/libgomp/config/linux/wait.h b/libgomp/config/linux/wait.h
index 29d745f7141..17b7ef11c96 100644
--- a/libgomp/config/linux/wait.h
+++ b/libgomp/config/linux/wait.h
@@ -44,21 +44,16 @@ 
 extern int gomp_futex_wait, gomp_futex_wake;
 
 #include <futex.h>
-
+#include <spin.h>
 static inline int do_spin (int *addr, int val)
 {
-  unsigned long long i, count = gomp_spin_count_var;
+  unsigned long long count = gomp_spin_count_var;
 
   if (__builtin_expect (__atomic_load_n (&gomp_managed_threads,
                                          MEMMODEL_RELAXED)
                         > gomp_available_cpus, 0))
     count = gomp_throttled_spin_count_var;
-  for (i = 0; i < count; i++)
-    if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val, 0))
-      return 0;
-    else
-      cpu_relax ();
-  return 1;
+  return do_spin_for_count (addr, val, count);
 }
 
 static inline void do_wait (int *addr, int val)
diff --git a/libgomp/config/linux/x86/localfn.h b/libgomp/config/linux/x86/localfn.h
new file mode 100644
index 00000000000..379aced99ee
--- /dev/null
+++ b/libgomp/config/linux/x86/localfn.h
@@ -0,0 +1,19 @@ 
+#ifdef __x86_64__
+static inline void
+gomp_thread_delay(unsigned int count)
+{
+  unsigned long long i;
+  for (i = 0; i < count * gomp_thread_delay_count; i++)
+    __builtin_ia32_pause ();
+}
+
+#define RUNLOCALFN(a, b, c)  \
+  do \
+    { \
+      gomp_thread_delay(c); \
+      a (b); \
+    } \
+  while (0)
+#else
+# include "../../../../include/localfn.h"
+#endif
diff --git a/libgomp/config/linux/x86/mutex.c b/libgomp/config/linux/x86/mutex.c
new file mode 100644
index 00000000000..5a14efb522e
--- /dev/null
+++ b/libgomp/config/linux/x86/mutex.c
@@ -0,0 +1,66 @@ 
+#include "../mutex.c"
+
+#ifdef __x86_64__
+static inline int
+do_spin_for_count_generic (int *addr, int val, unsigned long long count)
+{
+  unsigned long long i;
+  for (i = 0; i < count; i++)
+    if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val,
+			  0))
+      return 0;
+    else
+      cpu_relax ();
+  return 1;
+}
+
+#ifndef __WAITPKG__
+#pragma GCC push_options
+#pragma GCC target("waitpkg")
+#define __DISABLE_WAITPKG__
+#endif /* __WAITPKG__ */
+
+static inline unsigned long long __rdtsc(void)
+{
+  unsigned long long var;
+  unsigned int hi, lo;
+
+  __asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
+
+  var = ((unsigned long long)hi << 32) | lo;
+  return var;
+}
+
+#define PAUSE_TP 200
+static inline int
+do_spin_for_backoff_tpause (int *addr, int val, unsigned long long count)
+{
+  unsigned int ctrl = 1;
+  unsigned long long wait_time = 1;
+  unsigned long long mask = 1ULL << __builtin_ia32_bsrdi(count * PAUSE_TP);
+  do
+    {
+      __builtin_ia32_tpause (ctrl, wait_time + __rdtsc());
+      wait_time = (wait_time << 1) | 1;
+      if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val,
+			    0))
+	return 0;
+    }
+  while ((wait_time & mask) == 0);
+  return 1;
+}
+
+#ifdef __DISABLE_WAITPKG__
+#undef __DISABLE_WAITPKG__
+#pragma GCC pop_options
+#endif /* __DISABLE_WAITPKG__ */
+
+int do_spin_for_count (int *addr, int val, unsigned long long count)
+{
+  if(__builtin_cpu_supports ("waitpkg"))
+    return do_spin_for_backoff_tpause(addr, val, count);
+  else
+    return do_spin_for_count_generic(addr, val, count);
+}
+
+#endif
diff --git a/libgomp/config/linux/x86/spin.h b/libgomp/config/linux/x86/spin.h
new file mode 100644
index 00000000000..fb8529af026
--- /dev/null
+++ b/libgomp/config/linux/x86/spin.h
@@ -0,0 +1,5 @@ 
+#ifdef __x86_64__
+extern int do_spin_for_count (int *, int, unsigned long long) ;
+#else
+# include "../spin.h"
+#endif
diff --git a/libgomp/env.c b/libgomp/env.c
index f24484d7f70..6a96a4b0df1 100644
--- a/libgomp/env.c
+++ b/libgomp/env.c
@@ -106,6 +106,7 @@  gomp_mutex_t gomp_managed_threads_lock;
 #endif
 unsigned long gomp_available_cpus = 1, gomp_managed_threads = 1;
 unsigned long long gomp_spin_count_var, gomp_throttled_spin_count_var;
+unsigned long long gomp_thread_delay_count;
 unsigned long *gomp_nthreads_var_list, gomp_nthreads_var_list_len;
 char *gomp_bind_var_list;
 unsigned long gomp_bind_var_list_len;
@@ -2419,6 +2420,9 @@  initialize_env (void)
   else if (all != NULL && gomp_get_icv_flag (all->flags, GOMP_ICV_WAIT_POLICY))
     wait_policy = all->icvs.wait_policy;
 
+  if (!parse_spincount ("GOMP_DELAYCOUNT", &gomp_thread_delay_count))
+    gomp_thread_delay_count = 300;
+
   if (!parse_spincount ("GOMP_SPINCOUNT", &gomp_spin_count_var))
     {
       /* Using a rough estimation of 100000 spins per msec,
diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index 4d2bfab4b71..c3ccf247f6c 100644
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -596,6 +596,7 @@  extern bool gomp_cancel_var;
 extern enum gomp_target_offload_t gomp_target_offload_var;
 extern int gomp_max_task_priority_var;
 extern unsigned long long gomp_spin_count_var, gomp_throttled_spin_count_var;
+extern unsigned long long gomp_thread_delay_count;
 extern unsigned long gomp_available_cpus, gomp_managed_threads;
 extern unsigned long *gomp_nthreads_var_list, gomp_nthreads_var_list_len;
 extern char *gomp_bind_var_list;
diff --git a/libgomp/team.c b/libgomp/team.c
index 54dfca8080a..2a5aff72654 100644
--- a/libgomp/team.c
+++ b/libgomp/team.c
@@ -30,6 +30,7 @@ 
 #include "pool.h"
 #include <stdlib.h>
 #include <string.h>
+#include "localfn.h"
 
 #ifdef LIBGOMP_USE_PTHREADS
 pthread_attr_t gomp_thread_attr;
@@ -62,7 +63,6 @@  struct gomp_thread_start_data
   pthread_t handle;
 };
 
-
 /* This function is a pthread_create entry point.  This contains the idle
    loop in which a thread waits to be called up to become part of a team.  */
 
@@ -111,7 +111,8 @@  gomp_thread_start (void *xdata)
 
       gomp_barrier_wait (&team->barrier);
 
-      local_fn (local_data);
+      RUNLOCALFN(local_fn, local_data, thr->ts.team_id);
+
       gomp_team_barrier_wait_final (&team->barrier);
       gomp_finish_task (task);
       gomp_barrier_wait_last (&team->barrier);
@@ -126,7 +127,8 @@  gomp_thread_start (void *xdata)
 	  struct gomp_team *team = thr->ts.team;
 	  struct gomp_task *task = thr->task;
 
-	  local_fn (local_data);
+	  RUNLOCALFN(local_fn, local_data, thr->ts.team_id);
+
 	  gomp_team_barrier_wait_final (&team->barrier);
 	  gomp_finish_task (task);