Improve threading on Solaris, according to SF patch #460269, submitted

by bbrox@bbrox.org / lionel.ulmer@free.fr.

This adds a configure check and if all goes well turns on the
PTHREAD_SCOPE_SYSTEM thread attribute for new threads.

This should remove the need to add tiny sleeps at the start of threads
to allow other threads to be scheduled.

Python/thread_pthread.h

@@ -135,16 +135,21 @@ PyThread_start_new_thread(void (*func)(void *), void *arg)
 {
 	pthread_t th;
 	int success;
-#ifdef THREAD_STACK_SIZE
+#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
 	pthread_attr_t attrs;
 #endif
 	dprintf(("PyThread_start_new_thread called\n"));
 	if (!initialized)
 		PyThread_init_thread();
 
-#ifdef THREAD_STACK_SIZE
+#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
 	pthread_attr_init(&attrs);
+#endif
+#ifdef THREAD_STACK_SIZE
 	pthread_attr_setstacksize(&attrs, THREAD_STACK_SIZE);
+#endif
+#ifdef PTHREAD_SYSTEM_SCHED_SUPPORTED
+        pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM);
 #endif
 	success = pthread_create(&th, 
 #if defined(PY_PTHREAD_D4)
@@ -160,7 +165,7 @@ PyThread_start_new_thread(void (*func)(void *), void *arg)
 				 func,
 				 arg
 #elif defined(PY_PTHREAD_STD)
-#ifdef THREAD_STACK_SIZE
+#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
 				 &attrs,
 #else
 				 (pthread_attr_t*)NULL,

acconfig.h

@@ -155,6 +155,9 @@
 /* The number of bytes in a pthread_t. */
 #undef SIZEOF_PTHREAD_T
 
+/* Defined if PTHREAD_SCOPE_SYSTEM supported. */
+#undef PTHREAD_SYSTEM_SCHED_SUPPORTED
+
 /* sizeof(void *) */
 #undef SIZEOF_VOID_P
 

configure.in

@@ -903,6 +903,7 @@ then
     CC="$CC -Kpthread"
     AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBOBJS="$LIBOBJS thread.o"
 else
     if test ! -z "$with_threads" -a -d "$with_threads"
@@ -927,14 +928,18 @@ else
     AC_CHECK_LIB(pthread, pthread_create, [AC_DEFINE(WITH_THREAD)
     case $ac_sys_system in
       Darwin*) ;;
-      *) AC_DEFINE(_POSIX_THREADS);;
+      *) AC_DEFINE(_POSIX_THREADS)
+         posix_threads=yes
+         ;;
     esac
     LIBS="-lpthread $LIBS"
     LIBOBJS="$LIBOBJS thread.o"],[
     AC_CHECK_FUNC(pthread_detach, [AC_DEFINE(WITH_THREAD)
     case $ac_sys_system in
       Darwin*) ;;
-      *) AC_DEFINE(_POSIX_THREADS);;
+      *) AC_DEFINE(_POSIX_THREADS)
+         posix_threads=yes
+         ;;
     esac
     LIBOBJS="$LIBOBJS thread.o"],[
     AC_CHECK_HEADER(kernel/OS.h, [AC_DEFINE(WITH_THREAD)
@@ -942,27 +947,53 @@ else
     LIBOBJS="$LIBOBJS thread.o"],[
     AC_CHECK_LIB(pthreads, pthread_create, [AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBS="$LIBS -lpthreads"
     LIBOBJS="$LIBOBJS thread.o"], [
     AC_CHECK_LIB(c_r, pthread_create, [AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBS="$LIBS -lc_r"
     LIBOBJS="$LIBOBJS thread.o"], [
     AC_CHECK_LIB(thread, __d6_pthread_create, [AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBS="$LIBS -lthread"
     LIBOBJS="$LIBOBJS thread.o"], [
     AC_CHECK_LIB(pthread, __pthread_create_system, [AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBS="$LIBS -lpthread"
     LIBOBJS="$LIBOBJS thread.o"], [
     AC_CHECK_LIB(cma, pthread_create, [AC_DEFINE(WITH_THREAD)
     AC_DEFINE(_POSIX_THREADS)
+    posix_threads=yes
     LIBS="$LIBS -lcma"
     LIBOBJS="$LIBOBJS thread.o"],[
     USE_THREAD_MODULE="#"])
     ])])])])])])])])])
 
+    if test "$posix_threads" = "yes"; then
+      AC_MSG_CHECKING(if PTHREAD_SCOPE_SYSTEM is supported)
+      AC_CACHE_VAL(ac_cv_pthread_system_supported,
+      [AC_TRY_RUN([#include <pthread.h>
+      void *foo(void *parm) {
+        return NULL;
+      }
+      main() {
+        pthread_attr_t attr;
+        if (pthread_attr_init(&attr)) exit(-1);
+        if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM)) exit(-1);
+        if (pthread_create(NULL, &attr, foo, NULL)) exit(-1);
+        exit(0);
+      }], ac_cv_pthread_system_supported=yes, ac_cv_pthread_system_supported=no)
+      ])
+      AC_MSG_RESULT($ac_cv_pthread_system_supported)
+      if test "$ac_cv_pthread_system_supported" = "yes"; then
+        AC_DEFINE(PTHREAD_SYSTEM_SCHED_SUPPORTED)
+      fi
+    fi
+
     AC_CHECK_LIB(mpc, usconfig, [AC_DEFINE(WITH_THREAD)
     LIBS="$LIBS -lmpc"
     LIBOBJS="$LIBOBJS thread.o"

pyconfig.h.in

@@ -214,6 +214,9 @@
 /* The number of bytes in a pthread_t. */
 #undef SIZEOF_PTHREAD_T
 
+/* Defined if PTHREAD_SCOPE_SYSTEM supported. */
+#undef PTHREAD_SYSTEM_SCHED_SUPPORTED
+
 /* Define to `int' if <sys/types.h> doesn't define.  */
 #undef socklen_t