//#include "FIFORunner.ih"
// Custom includes
+#include <signal.h>
+#include <time.h>
+#include "../Utils/Exception.hh"
+#include "../Utils/senfassert.hh"
//#include "FIFORunner.mpp"
#define prefix_
///////////////////////////////cc.p////////////////////////////////////////
+prefix_ senf::scheduler::FIFORunner::FIFORunner()
+ : tasks_ (), next_ (tasks_.end()), watchdogMs_ (1000), watchdogCount_(0), hangCount_ (0)
+{
+ struct sigevent ev;
+ ::memset(&ev, 0, sizeof(ev));
+ ev.sigev_notify = SIGEV_SIGNAL;
+ ev.sigev_signo = SIGURG;
+ ev.sigev_value.sival_ptr = this;
+ if (timer_create(CLOCK_MONOTONIC, &ev, &watchdogId_) < 0)
+ SENF_THROW_SYSTEM_EXCEPTION("timer_create()");
+
+ struct sigaction sa;
+ ::memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = &watchdog;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGURG, &sa, 0) < 0)
+ SENF_THROW_SYSTEM_EXCEPTION("sigaction()");
+
+ sigset_t mask;
+ sigemptyset(&mask);
+ sigaddset(&mask, SIGURG);
+ if (sigprocmask(SIG_UNBLOCK, &mask, 0) < 0)
+ SENF_THROW_SYSTEM_EXCEPTION("sigprocmask()");
+}
+
+prefix_ senf::scheduler::FIFORunner::~FIFORunner()
+{
+ timer_delete(watchdogId_);
+ signal(SIGURG, SIG_DFL);
+}
+
+// At the moment, the FIFORunner is not very efficient with many non-runnable tasks since the
+// complete list of tasks is traversed on each run().
+//
+// To optimize this, we woould need a way to find the relative ordering of two tasks in O(1) (at the
+// moment, this is an O(N) operation by traversing the list).
+//
+// One idea is, to give each task an 'order' value. Whenever a task is added at the end, it's order
+// value is set to the order value of the last task + 1. Whenever the order value such added exceeds
+// some threshold (e.g. 2^31 -1 or some such), the task list is traversed from beginning to end to
+// assign new consecutive order values. This O(N) operation is so seldom, that it is amortized over
+// a very long time.
+//
+// With this value at hand, we can do several optimizations: One idea would be the following: The
+// runnable set always has two types of tasks: There are tasks, which are heavily active and are
+// signaled constantly and other tasks which lie dormant most of the time. Those dormant tasks will
+// end up at the beginning of the task queue.
+//
+// With the above defined 'ordering' field available, we can manage an iterator pointing to the
+// first and the last runnable task. This will often help a lot since the group of runnable tasks
+// will mostly be localized to the end of the queue. only occasionally one of the dormant tasks will
+// be runnable. This additional traversal time will be amortized over a larger time.
+
prefix_ void senf::scheduler::FIFORunner::dequeue(TaskInfo * task)
{
TaskList::iterator i (TaskList::current(*task));
struct NullTask
: public senf::scheduler::FIFORunner::TaskInfo
{
+ NullTask() : senf::scheduler::FIFORunner::TaskInfo ("<null>") {}
void run() {};
};
}
// - We keep the next to-be-processed node in a class variable which is checked and updated
// whenever a node is removed.
NullTask null;
+ struct itimerspec timer;
+ timer.it_interval.tv_sec = watchdogMs_ / 1000;
+ timer.it_interval.tv_nsec = (watchdogMs_ % 1000) * 1000000ul;
+ timer.it_value.tv_sec = timer.it_interval.tv_sec;
+ timer.it_value.tv_nsec = timer.it_interval.tv_nsec;
tasks_.push_back(null);
TaskList::iterator end (TaskList::current(null));
next_ = tasks_.begin();
- while (next_ != end) {
- TaskInfo & task (*next_);
- if (task.runnable) {
- task.runnable = false;
- TaskList::iterator i (next_);
- ++ next_;
- tasks_.splice(tasks_.end(), tasks_, i);
- task.run();
+ try {
+ if (timer_settime(watchdogId_, 0, &timer, 0) < 0)
+ SENF_THROW_SYSTEM_EXCEPTION("timer_settime()");
+ while (next_ != end) {
+ TaskInfo & task (*next_);
+ if (task.runnable) {
+ task.runnable = false;
+ runningName_ = task.name;
+# ifdef SENF_DEBUG
+ runningBacktrace_ = task.backtrace;
+# endif
+ TaskList::iterator i (next_);
+ ++ next_;
+ tasks_.splice(tasks_.end(), tasks_, i);
+ watchdogCount_ = 1;
+ task.run();
+ }
+ else
+ ++ next_;
}
- else
- ++ next_;
}
+ catch (...) {
+ watchdogCount_ = 0;
+ timer.it_interval.tv_sec = 0;
+ timer.it_interval.tv_nsec = 0;
+ timer.it_value.tv_sec = 0;
+ timer.it_value.tv_nsec = 0;
+ timer_settime(watchdogId_, 0, &timer, 0);
+ tasks_.erase(end);
+ next_ = tasks_.end();
+ throw;
+ }
+ watchdogCount_ = 0;
+ timer.it_interval.tv_sec = 0;
+ timer.it_interval.tv_nsec = 0;
+ timer.it_value.tv_sec = 0;
+ timer.it_value.tv_nsec = 0;
+ if (timer_settime(watchdogId_, 0, &timer, 0) < 0)
+ SENF_THROW_SYSTEM_EXCEPTION("timer_settime()");
tasks_.erase(end);
next_ = tasks_.end();
}
+prefix_ void senf::scheduler::FIFORunner::watchdog(int, siginfo_t * si, void *)
+{
+ FIFORunner & runner (*static_cast<FIFORunner *>(si->si_value.sival_ptr));
+ if (runner.watchdogCount_ > 0) {
+ ++ runner.watchdogCount_;
+ if (runner.watchdogCount_ > 2) {
+ ++ runner.hangCount_;
+ write(1, "\n\n*** Scheduler task hanging: ", 30);
+ write(1, runner.runningName_.c_str(), runner.runningName_.size());
+ write(1, "\n", 1);
+#ifdef SENF_DEBUG
+ write(1, "Task was initialized at\n", 24);
+ write(1, runner.runningBacktrace_.c_str(), runner.runningBacktrace_.size());
+#endif
+ write(1, "\n", 1);
+ }
+ }
+}
+
///////////////////////////////cc.e////////////////////////////////////////
#undef prefix_
//#include "FIFORunner.mpp"
projects / senf.git / blobdiff