Added new routines from POSIX 1003.1j. This is alpha level code.

        * spin.c: New module implementing spin locks.
        * barrier.c: New module implementing barriers.
        * pthread.h (_POSIX_SPIN_LOCKS): defined.
        (_POSIX_BARRIERS): Defined.
        (pthread_spin_*): Defined.
        (pthread_barrier*): Defined.
        (PTHREAD_BARRIER_SERIAL_THREAD): Defined.
        * implement.h (pthread_spinlock_t_): Defined.
        (pthread_barrier_t_): Defined.
        (pthread_barrierattr_t_): Defined.

        * mutex.c (pthread_mutex_lock): Return with the error
        if an auto-initialiser initialisation fails.

        * nonportable.c (pthread_getprocessors_np): New; gets the
        number of available processors for the current process.

1 files changed, 67 insertions, 239 deletions

diff --git a/ANNOUNCE b/ANNOUNCE
index 4067979..bf9d431 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,4 +1,4 @@
-                 PTHREADS-WIN32 SNAPSHOT 2001-07-03

+                 PTHREADS-WIN32 SNAPSHOT 2001-??-??

                  ----------------------------------

        Web Site: http://sources.redhat.com/pthreads-win32/

       FTP Site: ftp://sources.redhat.com/pub/pthreads-win32

@@ -26,236 +26,41 @@ announcement for the list of contributors.
 Changes since the last snapshot

 -------------------------------

 

------------------------

-Additions to Scheduling

------------------------

-New routines:

-	pthread_attr_setinheritsched()

-	pthread_attr_getinheritsched()

-	pthread_attr_setschedpolicy()

-	pthread_attr_getschedpolicy()

-	sched_setscheduler()

-	sched_getscheduler()

-	sched_rr_get_interval()

-Now defined:

-	_POSIX_THREAD_PRIORITY_SCHEDULING

-

-These routines complete the set required for defining

-_POSIX_THREAD_PRIORITY_SCHEDULING.

-

-

-sched_setscheduler

-sched_getscheduler

-------------------

-These routines will require patching to work with UWIN

-and any other system that provides it's own pid_t.

-Our pthread.h conditionally defines pid_t as a DWORD, which

-is the type returned by GetCurrentProcessId().

-

-The only supported policy is SCHED_OTHER, however, in

-order to provide semantic compatibility these routines

-verify the following:

-- that the process identified by pid exists;

-- that permission is granted to set or query the policy;

-The appropriate error is returned if either of these fail.

-On success, both routines return SCHED_OTHER.

-

-

-sched_rr_get_interval

----------------------

-Always returns -1 and sets errno to ENOTSUP. This is

-implemented as a macro. It returns ENOTSUP rather than

-ENOSYS because sched_get_priority_max() and

-sched_get_priority_min() are supported, but only for

-SCHED_OTHER.

-

-

-pthread_attr_setschedpolicy

-pthread_attr_getschedpolicy

----------------------------

-The only valid supported policy is SCHED_OTHER.

-Attempting to set other policies results in an ENOTSUP

-error.

-

-

-pthread_attr_setinheritsched

-pthread_attr_getinheritsched

-----------------------------

-The two possible values that can be set are

-PTHREAD_INHERIT_SCHED and PTHREAD_EXPLICIT_SCHED.

-

-Neither the POSIX standard nor the Single Unix Spec

-specifies which should be the default value.

-Consequently, implementations use different defaults,

-eg (from a scan of the web):

-

-PTHREAD_INHERIT_SCHED default:

-	HP, MKS Toolkit, QNX, AIX (?)

-

-PTHREAD_EXPLICIT_SCHED default:

-	IBM OS/400, Linux, Sun

-

-All Win32 threads are created with THREAD_PRIORITY_NORMAL.

-They do not inherit the priority of the parent thread or the

-process. This behaviour is equivalent to the following

-Pthreads defaults:

-

-	Inheritance:	PTHREAD_EXPLICIT_SCHED

-	Priority:		THREAD_PRIORITY_NORMAL

-

-These are also the defaults in pthreads-win32, and now

-reinforced by changes to the library which now actually

-use these values and routines. This choice maintains the

-notion that, from the Pthread point-of-view, Win32

-threads (those not created via pthread_create()) are

-treated as detached POSIX threads with default attribute

-values.

-

-

-------------------

-Changes to Mutexes

-------------------

-Background:

-Snapshot-2001-06-06 included Thomas Pfaff's enhancements

-to the mutex routines to improve speed. The improvements

-are very large on Win9x class systems where pthreads-win32

-previously used Win32 mutexes rather than critical

-sections as the underlying mechanism. Based on some new

-benchtest programs that have been run on a Win98 machine

-(and included in the tests directory), WNT systems speed

-has probably decreased a little. On Win9x the enhancements

-also resulted in speed improvements in other primitives

-which use mutexes internally, such as condition variables

-and read-write locks. Thomas also added mutex

-types to the library as described in the Single Unix

-Specification documentation, and as provided with

-the majority of major Unix and Linux Pthreads

-implementations.

-

-Overall, the library now provides far more consistent performance

-across the different Windows variants and greater compatibility.

-Future work will continue to improve on this.

-

-New changes:

-Changes have been made to further improve the speed of the

-default PTHREAD_MUTEX_NORMAL type (and therefore also

-PTHREAD_MUTEX_DEFAULT which is equivalent in pthreads-win32).

-

-Specifically, the library no longer sets or checks the real

-mutex owner when locking, unlocking, trylocking, or

-destroying PTHREAD_MUTEX_NORMAL mutexes. This saves

-significant overhead and results in measured speed increases

-of around 90 percent for non-blocking lock operations, and a

-slight improvement for blocking lock operations. Since the

-type of mutex used internally is PTHREAD_MUTEX_DEFAULT, this

-also results in additional speed improvements to CVs and R/W

-lock operations. Subjective observation shows an

-improvement of up to 30-35% in R/W locks

-(from tests/rwlock7.c). This is compared to the

-already improved snapshot-2001-06-06.

-

-The price paid for this improvement is that some checking

-for errors is not done for these mutex types. The onus

-is placed on the developer to check application code

-for logical errors, or use a safer mutex type such as

-PTHREAD_MUTEX_ERRORCHECK. For example, it is now

-possible for a non-owner thread to unlock or destroy

-a mutex of these types. However, because the owner

-is not simply left as NULL but set to a special anonymous

-owner value when locked and then reset to NULL when

-unlocked or destroyed, an error will ultimately eventuate

-when the owner thread subsequently attempts to unlock or

-destroy the mutex.

-

-These changes are consistent with both the behaviour exhibited

-by PTHREAD_MUTEX_NORMAL in other implementations and their

-documentation, including the Open Group documentation.

-

-

-------------

-Benchmarking

-------------

-There is a new but growing set a benchmarking programs in the

-"tests" directory. These should be runnable using the

-following command-lines corresponding to each of the possible

-library builds:

-

-MSVC:

-nmake clean VC-bench

-nmake clean VCE-bench

-nmake clean VSE-bench

-

-Mingw32:

-make clean GC-bench

-make clean GCE-bench

-

-UWIN:

-The benchtests are run as part of the testsuite.

-

-

-In this snapshot there are four benchtests timing

-various mutex senarios. They are:

-

-benchtest1 - Lock plus unlock on an unlocked mutex.

-benchtest2 - Lock plus unlock on a locked mutex.

-benchtest3 - Trylock on a locked mutex.

-benchtest4 - Trylock plus unlock on an unlocked mutex.

-

-

-Each test times up to three alternate synchronisation

-implementations as a reference, and then times each of

-the four mutex types provided by the library. Each is

-described below:

-

-Simple Critical Section

-- uses a simple Win32 critical section. There is no

-additional overhead for this case as there is in the

-remaining cases.

-

-POSIX mutex implemented using a Critical Section

-- The old implementation which uses runtime adaptation

-depending on the Windows variant being run on. When

-the pthreads DLL was run on WinNT or higher then

-POSIX mutexes would use Win32 Critical Sections.

-

-POSIX mutex implemented using a Win32 Mutex

-- The old implementation which uses runtime adaptation

-depending on the Windows variant being run on. When

-the pthreads DLL was run on Win9x then POSIX mutexes

-would use Win32 Mutexes (because TryEnterCriticalSection

-is not implemented on Win9x).

-

-PTHREAD_MUTEX_DEFAULT

-PTHREAD_MUTEX_NORMAL

-PTHREAD_MUTEX_ERRORCHECK

-PTHREAD_MUTEX_RECURSIVE

-- The current implementation supports these mutex types.

-The underlying basis of POSIX mutexes is now the same

-irrespective of the Windows variant.

-

-

-In all benchtests, the operation is repeated a large

-number of times and an average is calculated. Loop

-overhead is measured and subtracted from all test times.

-

+----------------------------------

+New: Spin locks (alpha level code)

+----------------------------------

+These are part of POSIX 1003.1j. They are

+useful only on multiprocessor machines.

+

+        #define _POSIX_SPIN_LOCKS

+        pthread_spin_init()

+        pthread_spin_destroy()

+        pthread_spin_lock()

+        pthread_spin_unlock()

+        pthread_spin_trylock()

+

+--------------------------------

+New: Barriers (alpha level code)

+--------------------------------

+These are part of POSIX 1003.1j. They are generally

+useful.

+

+        #define _POSIX_BARRIERS

+        pthread_barrier_init()

+        pthread_barrier_destroy()

+        pthread_barrier_wait()

+        pthread_barrierattr_init()

+        pthread_barrierattr_destroy()

+        pthread_barrierattr_getpshared()

+        pthread_barrierattr_setpshared()

 

 ---------

 Bug fixes

 ---------

-Pthread_create now sets the priority of the new thread

-from the value set in the thread attribute. 

-- from Ralf.Brese@pdb4.siemens.de.

+In pthread_mutex_lock, return the error if an

+auto-initialiser initialisation fails.

 

-In the last snapshot I introduced a "lost signal" bug into

-the condition variables code.

-- fixed by Alexander Terekhov

-- reported by Timur Aydin taydin@snet.net

-

-

----------

-New tests

----------

-Several new tests have been added to the test suite.

+_POSIX_READER_WRITER_LOCKS is now defined.

 

 

 ---------------------------

@@ -327,16 +132,19 @@ reliably.
 Level of standards conformance

 ------------------------------

 

-The following POSIX 1003.1c 1995 and POSIX 1003.1b options are defined:

+The following POSIX 1003.1c/1b/1j options are defined:

 

       _POSIX_THREADS

       _POSIX_THREAD_SAFE_FUNCTIONS

       _POSIX_THREAD_ATTR_STACKSIZE

       _POSIX_THREAD_PRIORITY_SCHEDULING

       _POSIX_SEMAPHORES

+      _POSIX_READER_WRITER_LOCKS

+      _POSIX_SPIN_LOCKS

+      _POSIX_BARRIERS

 

 

-The following POSIX 1003.1c 1995 options are not defined:

+The following POSIX 1003.1c options are not defined:

 

       _POSIX_THREAD_ATTR_STACKADDR

       _POSIX_THREAD_PRIO_INHERIT

@@ -415,7 +223,7 @@ The following functions are implemented:
       pthread_cond_broadcast  

 

       ---------------------------

-      Read/Write Locks:

+      Read/Write Locks - POSIX 1j

       ---------------------------

       pthread_rwlock_init

       pthread_rwlock_destroy

@@ -426,17 +234,37 @@ The following functions are implemented:
       pthread_rwlock_unlock

 

       ---------------------------

-      Semaphores

+      Spin Locks - POSIX 1j

+      ---------------------------

+      pthread_spin_init

+      pthread_spin_destroy

+      pthread_spin_lock

+      pthread_spin_unlock

+      pthread_spin_trylock

+

+      ---------------------------

+      Barriers - POSIX 1j

+      ---------------------------

+      pthread_barrier_init

+      pthread_barrier_destroy

+      pthread_barrier_wait

+      pthread_barrierattr_init

+      pthread_barrierattr_destroy

+      pthread_barrierattr_getpshared

+      pthread_barrierattr_setpshared

+

+      ---------------------------

+      Semaphores - POSIX 1b

       ---------------------------

-      sem_init               (POSIX 1b)

-      sem_destroy            (POSIX 1b)

-      sem_post               (POSIX 1b)

-      sem_wait               (POSIX 1b)

-      sem_trywait            (POSIX 1b)

-      sem_open               (POSIX 1b - returns an error ENOSYS)

-      sem_close              (POSIX 1b - returns an error ENOSYS)

-      sem_unlink             (POSIX 1b - returns an error ENOSYS)

-      sem_getvalue           (POSIX 1b - returns an error ENOSYS)

+      sem_init

+      sem_destroy

+      sem_post

+      sem_wait

+      sem_trywait

+      sem_open               (returns an error ENOSYS)

+      sem_close              (returns an error ENOSYS)

+      sem_unlink             (returns an error ENOSYS)

+      sem_getvalue           (returns an error ENOSYS)

 

       ---------------------------

       RealTime Scheduling