summaryrefslogtreecommitdiff
path: root/tests/README.benchtests
diff options
context:
space:
mode:
Diffstat (limited to 'tests/README.benchtests')
-rw-r--r--tests/README.benchtests97
1 files changed, 0 insertions, 97 deletions
diff --git a/tests/README.benchtests b/tests/README.benchtests
deleted file mode 100644
index e02cb3e..0000000
--- a/tests/README.benchtests
+++ /dev/null
@@ -1,97 +0,0 @@
-
-------------
-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.
-
-
-Mutex benchtests
-----------------
-
-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, and should therefore
-have consistent performance.
-
-
-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.
-
-Comment on the results
-----------------------
-The gain in performance for Win9x systems is enormous - up to
-40 times faster for unlocked mutexes (2 times faster for locked
-mutexes).
-
-Pthread_mutex_trylock also appears to be faster for locked mutexes.
-
-The price for the new consistency between WinNT and Win9x is
-slower performance (up to twice as long) across a lock/unlock
-sequence. It is difficult to get a good split timing for lock
-and unlock operations, but by code inspection, it is the unlock
-operation that is slowing the pair down in comparison with the
-old-style CS mutexes, even for the fast PTHREAD_MUTEX_NORMAL mutex
-type with no other waiting threads. However, comparitive
-performance for operations on already locked mutexes is very close.
-
-When this is translated to real-world applications, the overall
-camparitive performance should be almost identical on NT class
-systems. That is, applications with heavy mutex contention should
-have almost equal performance, while applications with only light
-mutex contention should also have almost equal performance because
-the most critical operation in this case is the lock operation.
-
-Overall, the newer pthreads-win32 mutex routines are only slower
-(on NT class systems) where and when it is least critical.
-
-Thanks go to Thomas Pfaff for the current implementation of mutex
-routines.