diff options
| -rw-r--r-- | build2/operation.cxx | 2 | ||||
| -rw-r--r-- | build2/scheduler.cxx | 40 | ||||
| -rw-r--r-- | build2/scheduler.hxx | 10 |
3 files changed, 37 insertions, 15 deletions
diff --git a/build2/operation.cxx b/build2/operation.cxx index 62f82d3..82b546c 100644 --- a/build2/operation.cxx +++ b/build2/operation.cxx @@ -289,7 +289,7 @@ namespace build2 mg = sched.monitor ( target_count, init - incr, - [init, incr, what] (size_t c) -> size_t + [init, incr, &what] (size_t c) -> size_t { size_t p ((init - c) * 100 / init); size_t s (skip_count.load (memory_order_relaxed)); diff --git a/build2/scheduler.cxx b/build2/scheduler.cxx index 51863ab..fa46dbe 100644 --- a/build2/scheduler.cxx +++ b/build2/scheduler.cxx @@ -186,6 +186,23 @@ namespace build2 try { shutdown (); } catch (system_error&) {} } + void scheduler:: + wait_idle () + { + lock l (mutex_); + + while (active_ != init_active_) + { + l.unlock (); + this_thread::yield (); + l.lock (); + } + + assert (waiting_ == 0); + assert (ready_ == 0); + assert (starting_ == 0); + } + size_t scheduler:: shard_size (size_t mul, size_t div) const { @@ -294,8 +311,6 @@ namespace build2 void scheduler:: tune (size_t max_active) { - lock l (mutex_); - if (max_active == 0) max_active = orig_max_active_; @@ -305,15 +320,7 @@ namespace build2 // The scheduler must not be active though some threads might still be // comming off from finishing a task. So we busy-wait for them. // - while (active_ != init_active_) - { - l.unlock (); - this_thread::yield (); - l.lock (); - } - - assert (waiting_ == 0); - assert (ready_ == 0); + wait_idle (); max_active_ = max_active; } @@ -400,10 +407,18 @@ namespace build2 monitor (atomic_count& c, size_t t, function<size_t (size_t)> f) { assert (monitor_count_ == nullptr && t != 0); + + // While the scheduler must not be active, some threads might still be + // comming off from finishing a task and trying to report progress. So we + // busy-wait for them (also in ~monitor_guard()). + // + wait_idle (); + monitor_count_ = &c; monitor_tshold_.store (t, memory_order_relaxed); monitor_init_ = c.load (memory_order_relaxed); monitor_func_ = move (f); + return monitor_guard (this); } @@ -627,8 +642,7 @@ namespace build2 s.ready_condv_.notify_one (); } - // Become idle and wait for a notification (note that task_ is false - // here). + // Become idle and wait for a notification. // s.idle_++; s.idle_condv_.wait (l); diff --git a/build2/scheduler.hxx b/build2/scheduler.hxx index f79ca3e..20e5128 100644 --- a/build2/scheduler.hxx +++ b/build2/scheduler.hxx @@ -160,6 +160,7 @@ namespace build2 // If the maximum threads or task queue depth arguments are unspecified, // then appropriate defaults are used. // + explicit scheduler (size_t max_active, size_t init_active = 1, size_t max_threads = 0, @@ -197,7 +198,7 @@ namespace build2 void tune (size_t max_active); - // Return true if the scheduler is running serial. + // Return true if the scheduler is configured to run tasks serially. // // Note: can only be called from threads that have observed startup. // @@ -255,6 +256,7 @@ namespace build2 { if (s_ != nullptr) { + s_->wait_idle (); // See monitor() for details. s_->monitor_count_ = nullptr; s_->monitor_func_ = nullptr; } @@ -298,6 +300,12 @@ namespace build2 task_queue_ = nullptr; } + // Assuming all the task have been executed, busy-wait for all the threads + // to become idle. Normally you don't need to call this function directly. + // + void + wait_idle (); + // Return the number of hardware threads or 0 if unable to determine. // static size_t |