--- /dev/null
+/* Copyright (c) 2009-2015. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+/** \file RawContext.cpp
+ * Fast context switching inspired from SystemV ucontexts.
+ *
+ * In contrast to System V context, it does not touch the signal mask
+ * which avoids making a system call (at least on Linux).
+ */
+
+#include <math.h>
+
+#include <utility>
+#include <functional>
+
+#include "src/internal_config.h"
+
+#include "xbt/log.h"
+#include "xbt/parmap.h"
+#include "xbt/dynar.h"
+
+#include "smx_private.h"
+#include "smx_private.hpp"
+#include "mc/mc.h"
+
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
+
+// ***** Class definitions
+
+namespace simgrid {
+namespace simix {
+
+class RawContext;
+class RawContextFactory;
+
+class RawContext : public Context {
+protected:
+ void* stack_ = nullptr;
+ /** pointer to top the stack stack */
+ void* stack_top_ = nullptr;
+public:
+ friend class RawContextFactory;
+ RawContext(std::function<void()> code,
+ void_pfn_smxprocess_t cleanup_func,
+ smx_process_t process);
+ ~RawContext();
+public:
+ static void wrapper(void* arg);
+ void stop() override;
+ void suspend() override;
+ void resume();
+private:
+ void suspend_serial();
+ void suspend_parallel();
+ void resume_serial();
+ void resume_parallel();
+};
+
+class RawContextFactory : public ContextFactory {
+public:
+ RawContextFactory();
+ ~RawContextFactory();
+ RawContext* create_context(std::function<void()> code,
+ void_pfn_smxprocess_t, smx_process_t process) override;
+ void run_all() override;
+private:
+ void run_all_adaptative();
+ void run_all_serial();
+ void run_all_parallel();
+};
+
+ContextFactory* raw_factory()
+{
+ XBT_VERB("Using raw contexts. Because the glibc is just not good enough for us.");
+ return new RawContextFactory();
+}
+
+}
+}
+
+// ***** Loads of static stuff
+
+#if HAVE_THREAD_CONTEXTS
+static xbt_parmap_t raw_parmap;
+static simgrid::simix::RawContext** raw_workers_context; /* space to save the worker context in each thread */
+static uintptr_t raw_threads_working; /* number of threads that have started their work */
+static xbt_os_thread_key_t raw_worker_id_key; /* thread-specific storage for the thread id */
+#endif
+static unsigned long raw_process_index = 0; /* index of the next process to run in the
+ * list of runnable processes */
+static simgrid::simix::RawContext* raw_maestro_context;
+
+static bool raw_context_parallel = false;
+
+// ***** Raw context routines
+
+typedef void (*rawctx_entry_point_t)(void *);
+
+typedef void* raw_stack_t;
+extern "C" raw_stack_t raw_makecontext(void* malloced_stack, int stack_size,
+ rawctx_entry_point_t entry_point, void* arg);
+extern "C" void raw_swapcontext(raw_stack_t* old, raw_stack_t new_context);
+
+// TODO, we should handle FP, MMX and the x87 control-word (for x86 and x86_64)
+
+#if SIMGRID_PROCESSOR_x86_64
+__asm__ (
+#if defined(__APPLE__)
+ ".text\n"
+ ".globl _raw_makecontext\n"
+ "_raw_makecontext:\n"
+#elif defined(_WIN32)
+ ".text\n"
+ ".globl raw_makecontext\n"
+ "raw_makecontext:\n"
+#else
+ ".text\n"
+ ".globl raw_makecontext\n"
+ ".type raw_makecontext,@function\n"
+ "raw_makecontext:\n"/* Calling convention sets the arguments in rdi, rsi, rdx and rcx, respectively */
+#endif
+ " mov %rdi,%rax\n" /* stack */
+ " add %rsi,%rax\n" /* size */
+ " andq $-16, %rax\n" /* align stack */
+ " movq $0, -8(%rax)\n" /* @return for func */
+ " mov %rdx,-16(%rax)\n" /* func */
+ " mov %rcx,-24(%rax)\n" /* arg/rdi */
+ " movq $0, -32(%rax)\n" /* rsi */
+ " movq $0, -40(%rax)\n" /* rdx */
+ " movq $0, -48(%rax)\n" /* rcx */
+ " movq $0, -56(%rax)\n" /* r8 */
+ " movq $0, -64(%rax)\n" /* r9 */
+ " movq $0, -72(%rax)\n" /* rbp */
+ " movq $0, -80(%rax)\n" /* rbx */
+ " movq $0, -88(%rax)\n" /* r12 */
+ " movq $0, -96(%rax)\n" /* r13 */
+ " movq $0, -104(%rax)\n" /* r14 */
+ " movq $0, -112(%rax)\n" /* r15 */
+ " sub $112,%rax\n"
+ " ret\n"
+);
+
+__asm__ (
+#if defined(__APPLE__)
+ ".text\n"
+ ".globl _raw_swapcontext\n"
+ "_raw_swapcontext:\n"
+#elif defined(_WIN32)
+ ".text\n"
+ ".globl raw_swapcontext\n"
+ "raw_swapcontext:\n"
+#else
+ ".text\n"
+ ".globl raw_swapcontext\n"
+ ".type raw_swapcontext,@function\n"
+ "raw_swapcontext:\n" /* Calling convention sets the arguments in rdi and rsi, respectively */
+#endif
+ " push %rdi\n"
+ " push %rsi\n"
+ " push %rdx\n"
+ " push %rcx\n"
+ " push %r8\n"
+ " push %r9\n"
+ " push %rbp\n"
+ " push %rbx\n"
+ " push %r12\n"
+ " push %r13\n"
+ " push %r14\n"
+ " push %r15\n"
+ " mov %rsp,(%rdi)\n" /* old */
+ " mov %rsi,%rsp\n" /* new */
+ " pop %r15\n"
+ " pop %r14\n"
+ " pop %r13\n"
+ " pop %r12\n"
+ " pop %rbx\n"
+ " pop %rbp\n"
+ " pop %r9\n"
+ " pop %r8\n"
+ " pop %rcx\n"
+ " pop %rdx\n"
+ " pop %rsi\n"
+ " pop %rdi\n"
+ " ret\n"
+);
+#elif SIMGRID_PROCESSOR_i686
+__asm__ (
+#if defined(__APPLE__) || defined(_WIN32)
+ ".text\n"
+ ".globl _raw_makecontext\n"
+ "_raw_makecontext:\n"
+#else
+ ".text\n"
+ ".globl raw_makecontext\n"
+ ".type raw_makecontext,@function\n"
+ "raw_makecontext:\n"
+#endif
+ " movl 4(%esp),%eax\n" /* stack */
+ " addl 8(%esp),%eax\n" /* size */
+ " andl $-16, %eax\n" /* align stack */
+ " movl 12(%esp),%ecx\n" /* func */
+ " movl 16(%esp),%edx\n" /* arg */
+ " movl %edx, -4(%eax)\n"
+ " movl $0, -8(%eax)\n" /* @return for func */
+ " movl %ecx,-12(%eax)\n"
+ " movl $0, -16(%eax)\n" /* ebp */
+ " movl $0, -20(%eax)\n" /* ebx */
+ " movl $0, -24(%eax)\n" /* esi */
+ " movl $0, -28(%eax)\n" /* edi */
+ " subl $28,%eax\n"
+ " retl\n"
+);
+
+__asm__ (
+#if defined(__APPLE__) || defined(_WIN32)
+ ".text\n"
+ ".globl _raw_swapcontext\n"
+ "_raw_swapcontext:\n"
+#else
+ ".text\n"
+ ".globl raw_swapcontext\n"
+ ".type raw_swapcontext,@function\n"
+ "raw_swapcontext:\n"
+#endif
+ // Fetch the parameters:
+ " movl 4(%esp),%eax\n" /* old (raw_stack_t*) */
+ " movl 8(%esp),%edx\n" /* new (raw_stack_t) */
+ // Save registers of the current context on the stack:
+ " pushl %ebp\n"
+ " pushl %ebx\n"
+ " pushl %esi\n"
+ " pushl %edi\n"
+ // Save the current context (stack pointer) in *old:
+ " movl %esp,(%eax)\n"
+ // Switch to the stack of the new context:
+ " movl %edx,%esp\n"
+ // Pop the values of the new context:
+ " popl %edi\n"
+ " popl %esi\n"
+ " popl %ebx\n"
+ " popl %ebp\n"
+ // Return using the return address of the new context:
+ " retl\n"
+);
+#else
+
+
+/* If you implement raw contexts for other processors, don't forget to
+ update the definition of HAVE_RAW_CONTEXTS in tools/cmake/CompleteInFiles.cmake */
+
+raw_stack_t raw_makecontext(void* malloced_stack, int stack_size,
+ rawctx_entry_point_t entry_point, void* arg) {
+ THROW_UNIMPLEMENTED;
+}
+
+void raw_swapcontext(raw_stack_t* old, raw_stack_t new_context) {
+ THROW_UNIMPLEMENTED;
+}
+
+#endif
+
+// ***** Method definitions
+
+namespace simgrid {
+namespace simix {
+
+RawContextFactory::RawContextFactory()
+ : ContextFactory("RawContextFactory")
+{
+ raw_context_parallel = SIMIX_context_is_parallel();
+ if (raw_context_parallel) {
+#if HAVE_THREAD_CONTEXTS
+ int nthreads = SIMIX_context_get_nthreads();
+ xbt_os_thread_key_create(&raw_worker_id_key);
+ // TODO, lazily init
+ raw_parmap = nullptr;
+ raw_workers_context = xbt_new(RawContext*, nthreads);
+ raw_maestro_context = nullptr;
+#endif
+ // TODO, if(SIMIX_context_get_parallel_threshold() > 1) => choose dynamically
+ }
+}
+
+RawContextFactory::~RawContextFactory()
+{
+#if HAVE_THREAD_CONTEXTS
+ if (raw_parmap)
+ xbt_parmap_destroy(raw_parmap);
+ xbt_free(raw_workers_context);
+#endif
+}
+
+RawContext* RawContextFactory::create_context(std::function<void()> code,
+ void_pfn_smxprocess_t cleanup, smx_process_t process)
+{
+ return this->new_context<RawContext>(std::move(code),
+ cleanup, process);
+}
+
+void RawContext::wrapper(void* arg)
+{
+ RawContext* context = (RawContext*) arg;
+ (*context)();
+ context->stop();
+}
+
+RawContext::RawContext(std::function<void()> code,
+ void_pfn_smxprocess_t cleanup, smx_process_t process)
+ : Context(std::move(code), cleanup, process)
+{
+ if (has_code()) {
+ this->stack_ = SIMIX_context_stack_new();
+ this->stack_top_ = raw_makecontext(this->stack_,
+ smx_context_usable_stack_size,
+ RawContext::wrapper,
+ this);
+ } else {
+ if(process != nullptr && raw_maestro_context == nullptr)
+ raw_maestro_context = this;
+ if (MC_is_active())
+ MC_ignore_heap(
+ &raw_maestro_context->stack_top_,
+ sizeof(raw_maestro_context->stack_top_));
+ }
+}
+
+RawContext::~RawContext()
+{
+ SIMIX_context_stack_delete(this->stack_);
+}
+
+void RawContext::stop()
+{
+ Context::stop();
+ this->suspend();
+}
+
+void RawContextFactory::run_all()
+{
+ if (raw_context_parallel)
+ run_all_parallel();
+ else
+ run_all_serial();
+}
+
+void RawContextFactory::run_all_serial()
+{
+ smx_process_t first_process =
+ xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
+ raw_process_index = 1;
+ static_cast<RawContext*>(first_process->context)->resume_serial();
+}
+
+void RawContextFactory::run_all_parallel()
+{
+#if HAVE_THREAD_CONTEXTS
+ raw_threads_working = 0;
+ if (raw_parmap == nullptr)
+ raw_parmap = xbt_parmap_new(
+ SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode());
+ xbt_parmap_apply(raw_parmap,
+ [](void* arg) {
+ smx_process_t process = static_cast<smx_process_t>(arg);
+ RawContext* context = static_cast<RawContext*>(process->context);
+ context->resume_parallel();
+ },
+ simix_global->process_to_run);
+#else
+ xbt_die("You asked for a parallel execution, but you don't have any threads.");
+#endif
+}
+
+void RawContext::suspend()
+{
+ if (raw_context_parallel)
+ RawContext::suspend_parallel();
+ else
+ RawContext::suspend_serial();
+}
+
+void RawContext::suspend_serial()
+{
+ /* determine the next context */
+ RawContext* next_context = nullptr;
+ unsigned long int i;
+ i = raw_process_index++;
+ if (i < xbt_dynar_length(simix_global->process_to_run)) {
+ /* execute the next process */
+ XBT_DEBUG("Run next process");
+ next_context = (RawContext*) xbt_dynar_get_as(
+ simix_global->process_to_run, i, smx_process_t)->context;
+ }
+ else {
+ /* all processes were run, return to maestro */
+ XBT_DEBUG("No more process to run");
+ next_context = (RawContext*) raw_maestro_context;
+ }
+ SIMIX_context_set_current(next_context);
+ raw_swapcontext(&this->stack_top_, next_context->stack_top_);
+}
+
+void RawContext::suspend_parallel()
+{
+#if HAVE_THREAD_CONTEXTS
+ /* determine the next context */
+ smx_process_t next_work = (smx_process_t) xbt_parmap_next(raw_parmap);
+ RawContext* next_context = nullptr;
+
+ if (next_work != NULL) {
+ /* there is a next process to resume */
+ XBT_DEBUG("Run next process");
+ next_context = (RawContext*) next_work->context;
+ }
+ else {
+ /* all processes were run, go to the barrier */
+ XBT_DEBUG("No more processes to run");
+ uintptr_t worker_id = (uintptr_t)
+ xbt_os_thread_get_specific(raw_worker_id_key);
+ next_context = (RawContext*) raw_workers_context[worker_id];
+ XBT_DEBUG("Restoring worker stack %zu (working threads = %zu)",
+ worker_id, raw_threads_working);
+ }
+
+ SIMIX_context_set_current(next_context);
+ raw_swapcontext(&this->stack_top_, next_context->stack_top_);
+#endif
+}
+
+void RawContext::resume()
+{
+ if (raw_context_parallel)
+ resume_parallel();
+ else
+ resume_serial();
+}
+
+void RawContext::resume_serial()
+{
+ SIMIX_context_set_current(this);
+ raw_swapcontext(&raw_maestro_context->stack_top_, this->stack_top_);
+}
+
+void RawContext::resume_parallel()
+{
+#if HAVE_THREAD_CONTEXTS
+ uintptr_t worker_id = __sync_fetch_and_add(&raw_threads_working, 1);
+ xbt_os_thread_set_specific(raw_worker_id_key, (void*) worker_id);
+ RawContext* worker_context = (RawContext*) SIMIX_context_self();
+ raw_workers_context[worker_id] = worker_context;
+ XBT_DEBUG("Saving worker stack %zu", worker_id);
+ SIMIX_context_set_current(this);
+ raw_swapcontext(&worker_context->stack_top_, this->stack_top_);
+#else
+ xbt_die("Parallel execution disabled");
+#endif
+}
+
+/** @brief Resumes all processes ready to run. */
+void RawContextFactory::run_all_adaptative()
+{
+ unsigned long nb_processes = xbt_dynar_length(simix_global->process_to_run);
+ if (SIMIX_context_is_parallel()
+ && (unsigned long) SIMIX_context_get_parallel_threshold() < nb_processes) {
+ raw_context_parallel = true;
+ XBT_DEBUG("Runall // %lu", nb_processes);
+ this->run_all_parallel();
+ } else {
+ XBT_DEBUG("Runall serial %lu", nb_processes);
+ raw_context_parallel = false;
+ this->run_all_serial();
+ }
+}
+
+}
+}
