GH-1095 Refactor platform_timer and transaction_checktime_timer to us…

…e an enum for timer state instead of a bool expired. This allows differentiation between timer expired and interruption.

libraries/chain/controller.cpp

@@ -4533,7 +4533,7 @@ struct controller_impl {
       // validated.
       if (applying_block) {
          ilog("Interrupting apply block");
-         main_thread_timer.expire_now();
+         main_thread_timer.interrupt_timer();
       }
    }
 

libraries/chain/include/eosio/chain/platform_timer.hpp

@@ -7,8 +7,6 @@
 
 #include <atomic>
 
-#include <signal.h>
-
 namespace eosio { namespace chain {
 
 struct platform_timer {
@@ -17,7 +15,8 @@ struct platform_timer {
 
    void start(fc::time_point tp);
    void stop();
-   void expire_now();
+   void interrupt_timer();
+   void _expire_now(); // called by internal timer
 
    /* Sets a callback for when timer expires. Be aware this could might fire from a signal handling context and/or
       on any particular thread. Only a single callback can be registered at once; trying to register more will
@@ -35,9 +34,18 @@ struct platform_timer {
       _expiration_callback_data = user;
    }
 
-   std::atomic_bool expired = true;
+   enum class state_t {
+      running,
+      timed_out,
+      interrupted,
+      stopped
+   };
+   state_t timer_state() const { return _state; }
 
 private:
+   std::atomic<state_t> _state = state_t::stopped;
+
+
    struct impl;
    constexpr static size_t fwd_size = 8;
    fc::fwd<impl,fwd_size> my;

libraries/chain/include/eosio/chain/transaction_context.hpp

@@ -20,12 +20,13 @@ namespace eosio::chain {
          void start(fc::time_point tp);
          void stop();
 
+         platform_timer::state_t timer_state() const { return _timer.timer_state(); }
+
          /* Sets a callback for when timer expires. Be aware this could might fire from a signal handling context and/or
             on any particular thread. Only a single callback can be registered at once; trying to register more will
             result in an exception. Use nullptr to disable a previously set callback. */
          void set_expiration_callback(void(*func)(void*), void* user);
 
-         std::atomic_bool& expired;
       private:
          platform_timer& _timer;
 

libraries/chain/include/eosio/chain/wasm_interface_private.hpp

@@ -124,8 +124,7 @@ struct eosvmoc_tier {
                   return;
                if (executing_code_hash.load() == code_id) {
                   ilog("EOS VM OC tier up interrupting ${id}", ("id", code_id));
-                  eos_vm_oc_compile_interrupt = true;
-                  main_thread_timer.expire_now();
+                  main_thread_timer.interrupt_timer();
                }
             });
          }
@@ -172,7 +171,6 @@ struct eosvmoc_tier {
          const bool allow_oc_interrupt = attempt_tierup && context.is_applying_block() && context.trx_context.has_undo();
          auto ex = fc::make_scoped_exit([&]() {
             if (allow_oc_interrupt) {
-               eos_vm_oc_compile_interrupt = false;
                executing_code_hash.store({}); // indicate no longer executing
             }
          });
@@ -181,7 +179,7 @@ struct eosvmoc_tier {
          try {
             get_instantiated_module(code_hash, vm_type, vm_version, context.trx_context)->apply(context);
          } catch (const interrupt_exception& e) {
-            if (allow_oc_interrupt && eos_vm_oc_compile_interrupt) {
+            if (allow_oc_interrupt && main_thread_timer.timer_state() == platform_timer::state_t::interrupted) {
                ++eos_vm_oc_compile_interrupt_count;
                dlog("EOS VM OC compile complete interrupt of ${r} <= ${a}::${act} code ${h}, interrupt #${c}",
                     ("r", context.get_receiver())("a", context.get_action().account)
@@ -310,7 +308,6 @@ struct eosvmoc_tier {
       const wasm_interface::vm_type wasm_runtime_time;
       const wasm_interface::vm_oc_enable eosvmoc_tierup;
       large_atomic<digest_type> executing_code_hash{};
-      std::atomic<bool> eos_vm_oc_compile_interrupt{false};
       uint32_t eos_vm_oc_compile_interrupt_count{0}; // for testing
 
 #ifdef EOSIO_EOS_VM_OC_RUNTIME_ENABLED

libraries/chain/platform_timer_accuracy.cpp

@@ -39,9 +39,10 @@ void compute_and_print_timer_accuracy(platform_timer& timer) {
       for(unsigned int i = 0; i < loops; ++i) {
          auto start = std::chrono::high_resolution_clock::now();
          timer.start(fc::time_point(fc::time_point::now().time_since_epoch() + fc::microseconds(interval)));
-         while(!timer.expired) {}
+         while(timer.timer_state() == platform_timer::state_t::running) {}
          auto end = std::chrono::high_resolution_clock::now();
          int timer_slop = std::chrono::duration_cast<std::chrono::microseconds>(end-start).count() - interval;
+         timer.stop();
 
          //since more samples are run for the shorter expirations, weigh the longer expirations accordingly. This
          //helps to make a few results more fair. Two such examples: AWS c4&i5 xen instances being rather stable

libraries/chain/platform_timer_posix.cpp

@@ -21,7 +21,7 @@ struct platform_timer::impl {
 
    static void sig_handler(int, siginfo_t* si, void*) {
       platform_timer* self = (platform_timer*)si->si_value.sival_ptr;
-      self->expire_now();
+      self->_expire_now();
    }
 };
 
@@ -56,35 +56,42 @@ platform_timer::~platform_timer() {
 
 void platform_timer::start(fc::time_point tp) {
    if(tp == fc::time_point::maximum()) {
-      expired = false;
+      _state = state_t::running;
       return;
    }
    fc::microseconds x = tp.time_since_epoch() - fc::time_point::now().time_since_epoch();
    if(x.count() <= 0)
-      expired = true;
+      _state = state_t::timed_out;
    else {
       time_t secs = x.count() / 1000000;
       long nsec = (x.count() - (secs*1000000)) * 1000;
       struct itimerspec enable = {{0, 0}, {secs, nsec}};
-      expired = false;
+      _state = state_t::running;
       if(timer_settime(my->timerid, 0, &enable, NULL) != 0)
-         expired = true;
+         _state = state_t::timed_out;
    }
 }
 
-void platform_timer::expire_now() {
-   bool expected = false;
-   if (expired.compare_exchange_strong(expected, true)) {
+void platform_timer::_expire_now() {
+   state_t expected = state_t::running;
+   if (_state.compare_exchange_strong(expected, state_t::timed_out)) {
+      call_expiration_callback();
+   }
+}
+
+void platform_timer::interrupt_timer() {
+   state_t expected = state_t::running;
+   if (_state.compare_exchange_strong(expected, state_t::interrupted)) {
       call_expiration_callback();
    }
 }
 
 void platform_timer::stop() {
-   if(expired)
+   if(_state == state_t::stopped)
       return;
    struct itimerspec disable = {{0, 0}, {0, 0}};
    timer_settime(my->timerid, 0, &disable, NULL);
-   expired = true;
+   _state = state_t::stopped;
 }
 
 }

libraries/chain/transaction_context.cpp

@@ -14,8 +14,7 @@
 namespace eosio::chain {
 
    transaction_checktime_timer::transaction_checktime_timer(platform_timer& timer)
-         : expired(timer.expired), _timer(timer) {
-      expired = 0;
+         : _timer(timer) {
    }
 
    void transaction_checktime_timer::start(fc::time_point tp) {
@@ -489,11 +488,12 @@ namespace eosio::chain {
    }
 
    void transaction_context::checktime()const {
-      if(BOOST_LIKELY(transaction_timer.expired == false))
+      platform_timer::state_t expired = transaction_timer.timer_state();
+      if(BOOST_LIKELY(expired == platform_timer::state_t::running))
          return;
 
       auto now = fc::time_point::now();
-      if (explicit_billed_cpu_time && block_deadline > now) {
+      if (expired == platform_timer::state_t::interrupted) {
          EOS_THROW( interrupt_exception, "interrupt signaled, ran ${bt}us, start ${s}",
                     ("bt", now - pseudo_start)("s", start) );
       } else if( explicit_billed_cpu_time || deadline_exception_code == deadline_exception::code_value ) {

libraries/chain/webassembly/runtimes/eos-vm.cpp

@@ -29,7 +29,8 @@ namespace {
         guard(transaction_checktime_timer& timer, F&& func)
            : _timer(timer), _func(std::forward<F>(func)) {
            _timer.set_expiration_callback(&callback, this);
-           if(_timer.expired) {
+           platform_timer::state_t expired = _timer.timer_state();
+           if(expired == platform_timer::state_t::timed_out || expired == platform_timer::state_t::interrupted) {
               _func(); // it's harmless if _func is invoked twice
            }
         }