1 files changed, 83 insertions, 0 deletions
diff --git a/libs/context/performance/cycle_i386.hpp b/libs/context/performance/cycle_i386.hpp
new file mode 100644
index 0000000000..3e670077a1
--- /dev/null
+++ b/libs/context/performance/cycle_i386.hpp
@@ -0,0 +1,83 @@
+
+//          Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef CYCLE_I386_H
+#define CYCLE_I386_H
+
+#include <algorithm>
+#include <numeric>
+#include <cstddef>
+#include <vector>
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/cstdint.hpp>
+
+#define BOOST_CONTEXT_CYCLE
+
+typedef boost::uint64_t cycle_t;
+
+#if _MSC_VER
+inline
+cycle_t cycles()
+{
+    cycle_t c;
+    __asm {
+        cpuid 
+        rdtsc
+        mov dword ptr [c + 0], eax
+        mov dword ptr [c + 4], edx
+    }
+    return c;
+}
+#elif defined(__GNUC__) || \
+      defined(__INTEL_COMPILER) || defined(__ICC) || defined(_ECC) || defined(__ICL)
+inline
+cycle_t cycles()
+{
+    boost::uint32_t lo, hi;
+
+    __asm__ __volatile__ (
+        "xorl %%eax, %%eax\n"
+        "cpuid\n"
+        ::: "%eax", "%ebx", "%ecx", "%edx"
+    );
+    __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi) );
+    __asm__ __volatile__ (
+        "xorl %%eax, %%eax\n"
+        "cpuid\n"
+        ::: "%eax", "%ebx", "%ecx", "%edx"
+    );
+
+    return ( cycle_t)hi << 32 | lo; 
+}
+#else
+# error "this compiler is not supported"
+#endif
+
+struct measure_cycles
+{
+    cycle_t operator()()
+    {
+        cycle_t start( cycles() );
+        return cycles() - start;
+    }
+};
+
+inline
+cycle_t overhead_cycles()
+{
+    std::size_t iterations( 10);
+    std::vector< cycle_t >  overhead( iterations, 0);
+    for ( std::size_t i( 0); i < iterations; ++i)
+        std::generate(
+            overhead.begin(), overhead.end(),
+            measure_cycles() );
+    BOOST_ASSERT( overhead.begin() != overhead.end() );
+    return std::accumulate( overhead.begin(), overhead.end(), 0) / iterations;
+}
+
+#endif // CYCLE_I386_H