From 7802c695ef79b27fcc9c152efdf8c0b8ea49be2b Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Sun, 20 Apr 2008 17:00:58 +0000
Subject: [PATCH] sp_atomic_mt_test.cpp added.

[SVN r44640]
---
 test/sp_atomic_mt_test.cpp | 184 +++++++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 test/sp_atomic_mt_test.cpp

diff --git a/test/sp_atomic_mt_test.cpp b/test/sp_atomic_mt_test.cpp
new file mode 100644
index 0000000..bef549d
--- /dev/null
+++ b/test/sp_atomic_mt_test.cpp
@@ -0,0 +1,184 @@
+//#define USE_MUTEX
+//#define USE_RWLOCK
+
+#include <boost/config.hpp>
+
+#include <boost/shared_ptr.hpp>
+#include <boost/bind.hpp>
+
+#if defined( USE_RWLOCK )
+#include <boost/thread/shared_mutex.hpp>
+#include <boost/thread/locks.hpp>
+#endif
+
+#include <boost/detail/lightweight_mutex.hpp>
+#include <boost/detail/lightweight_test.hpp>
+#include <boost/detail/lightweight_thread.hpp>
+
+#include <cstdio>
+#include <ctime>
+
+//
+
+int const n = 1024 * 1024;
+
+struct X
+{
+    int v_; // version
+
+    unsigned a_;
+    unsigned b_;
+
+    X(): v_( 0 ), a_( 1 ), b_( 1 )
+    {
+    }
+
+    int get() const
+    {
+        return a_ * 7 + b_ * 11;
+    }
+
+    void set()
+    {
+        int tmp = get();
+
+        b_ = a_;
+        a_ = tmp;
+
+        ++v_;
+    }
+};
+
+static boost::shared_ptr<X> ps( new X );
+
+static boost::detail::lightweight_mutex lm;
+
+#if defined( USE_RWLOCK )
+static boost::shared_mutex rw;
+#endif
+
+static int tr = 0;
+
+void reader( int r )
+{
+    int k = 0;
+    unsigned s = 0;
+
+    for( int i = 0; i < n; ++k )
+    {
+#if defined( USE_MUTEX )
+
+        boost::detail::lightweight_mutex::scoped_lock lock( lm );
+
+        s += ps->get();
+
+        BOOST_TEST( ps->v_ >= i );
+        i = ps->v_;
+
+#elif defined( USE_RWLOCK )
+
+        boost::shared_lock<boost::shared_mutex> lock( rw );
+
+        s += ps->get();
+
+        BOOST_TEST( ps->v_ >= i );
+        i = ps->v_;
+
+#else
+
+        boost::shared_ptr<X> p2 = ps.atomic_load();
+
+        s += p2->get();
+
+        BOOST_TEST( p2->v_ >= i );
+        i = p2->v_;
+
+#endif
+    }
+
+    printf( "Reader %d: %9d iterations (%6.3fx), %u\n", r, k, (double)k / n, s );
+
+    boost::detail::lightweight_mutex::scoped_lock lock( lm );
+    tr += k;
+}
+
+void writer()
+{
+    for( int i = 0; i < n; ++i )
+    {
+#if defined( USE_MUTEX )
+
+        boost::detail::lightweight_mutex::scoped_lock lock( lm );
+
+        BOOST_TEST( ps->v_ == i );
+        ps->set();
+
+#elif defined( USE_RWLOCK )
+
+        boost::unique_lock<boost::shared_mutex> lock( rw );
+
+        BOOST_TEST( ps->v_ == i );
+        ps->set();
+
+#else
+
+        boost::shared_ptr<X> p2( new X( *ps ) );
+
+        BOOST_TEST( p2->v_ == i );
+        p2->set();
+
+        ps.atomic_store( p2 );
+
+#endif
+    }
+}
+
+#if defined( BOOST_HAS_PTHREADS )
+  char const * thmodel = "POSIX";
+#else
+  char const * thmodel = "Windows";
+#endif
+
+int const mr = 8; // reader threads
+int const mw = 1; // writer thread
+
+#if defined( USE_MUTEX )
+  char const * prim = "mutex";
+#elif defined( USE_RWLOCK )
+  char const * prim = "rwlock";
+#else
+  char const * prim = "atomics";
+#endif
+
+int main()
+{
+    using namespace std; // printf, clock_t, clock
+
+    printf( "Using %s threads: %dR + %dW threads, %d iterations, %s\n\n", thmodel, mr, mw, n, prim );
+
+    clock_t t = clock();
+
+    pthread_t a[ mr+mw ];
+
+    for( int i = 0; i < mr; ++i )
+    {
+        boost::detail::lw_thread_create( a[ i ], boost::bind( reader, i ) );
+    }
+
+    for( int i = mr; i < mr+mw; ++i )
+    {
+        boost::detail::lw_thread_create( a[ i ], writer );
+    }
+
+    for( int j = 0; j < mr+mw; ++j )
+    {
+        pthread_join( a[ j ], 0 );
+    }
+
+    t = clock() - t;
+
+    double ts = static_cast<double>( t ) / CLOCKS_PER_SEC;
+    printf( "%.3f seconds, %.3f reads per microsecond.\n", ts, tr / ts / 1e+6 );
+
+    return boost::report_errors();
+}