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align main context and scheduler to 64byte boundaries

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This commit is contained in:
Oliver Kowalke
2015-10-02 19:52:43 +02:00
parent 4cd1a910d9
commit 8662b5e253
1 changed files with 41 additions and 6 deletions
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47
src/context.cpp
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@@ -28,7 +28,7 @@ thread_local static std::size_t counter;
context_initializer::context_initializer() {
if ( 0 == counter++) {
//# if defined(BOOST_NO_CXX14_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
# if defined(BOOST_NO_CXX14_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
// allocate memory for main context and scheduler
constexpr std::size_t size = sizeof( context) + sizeof( scheduler);
void * vp = std::malloc( size);
@@ -46,8 +46,40 @@ context_initializer::context_initializer() {
make_dispatcher_context( sched) );
// make main context to active context
context::active_ = main_ctx;
//# else
//# endif
# else
constexpr std::size_t alignment = 64; // alignof( capture_t);
constexpr std::size_t ctx_size = sizeof( context);
constexpr std::size_t sched_size = sizeof( scheduler);
constexpr std::size_t size = 2 * alignment + ctx_size + sched_size;
void * vp = std::malloc( size);
if ( nullptr == vp) {
throw std::bad_alloc();
}
// reserve space for shift
void * vp1 = static_cast< char * >( vp) + sizeof( int);
// align context pointer
std::size_t space = ctx_size + alignment;
vp1 = std::align( alignment, ctx_size, vp1, space);
// reserves space for integer holding shifted size
int * shift = reinterpret_cast< int * >( static_cast< char * >( vp1) - sizeof( int) );
// store shifted size in fornt of context
* shift = static_cast< char * >( vp1) - static_cast< char * >( vp);
// main fiber context of this thread
context * main_ctx = new ( vp1) context( main_context);
vp1 = static_cast< char * >( vp1) + ctx_size;
// align scheduler pointer
space = sched_size + alignment;
vp1 = std::align( alignment, sched_size, vp1, space);
// scheduler of this thread
scheduler * sched = new ( vp1) scheduler();
// attach main context to scheduler
sched->set_main_context( main_ctx);
// create and attach dispatcher context to scheduler
sched->set_dispatcher_context(
make_dispatcher_context( sched) );
// make main context to active context
context::active_ = main_ctx;
# endif
}
}
@@ -58,10 +90,13 @@ context_initializer::~context_initializer() {
scheduler * sched = main_ctx->get_scheduler();
sched->~scheduler();
main_ctx->~context();
//# if defined(BOOST_NO_CXX14_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
# if defined(BOOST_NO_CXX14_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
std::free( main_ctx);
//# else
//# endif
# else
int * shift = reinterpret_cast< int * >( reinterpret_cast< char * >( main_ctx) - sizeof( int) );
void * vp = reinterpret_cast< char * >( main_ctx) - ( * shift);
std::free( vp);
# endif
}
}