Use "if constexpr" for EMPER_STATS compile-time feature

emper/Emper.hpp

+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright © 2020 Florian Schmaus
+#pragma once
+
+#include <emper-config.h>
+
+namespace emper {
+static const bool STATS =
+#ifdef EMPER_STATS
+		true
+#else
+		false
+#endif
+		;
+
+}	 // namespace emper

emper/Runtime.cpp

@@ -12,10 +12,11 @@
 #include <cstdlib>	// for rand, srand, abort
 #include <memory>		// for __shared_ptr_access, shared_ptr
 
-#include "Common.hpp"										 // for DIE_MSG_ERRNO, DIE, DIE_MSG
-#include "ContextManager.hpp"						 // for ContextManager
-#include "Debug.hpp"										 // for DBG, ABORT, LOGD, LOGE
-#include "Dispatcher.hpp"								 // for Dispatcher
+#include "Common.hpp"					 // for DIE_MSG_ERRNO, DIE, DIE_MSG
+#include "ContextManager.hpp"	 // for ContextManager
+#include "Debug.hpp"					 // for DBG, ABORT, LOGD, LOGE
+#include "Dispatcher.hpp"			 // for Dispatcher
+#include "Emper.hpp"
 #include "Fiber.hpp"										 // for Fiber
 #include "RuntimeStrategy.hpp"					 // for RuntimeStrategy
 #include "RuntimeStrategyStats.hpp"			 // for RuntimeStrategyStats
@@ -80,12 +81,12 @@ Runtime::Runtime(workerid_t workerCount, RuntimeStrategy& strategy, unsigned int
 		if (errno) DIE_MSG_ERRNO("pthread_create() failed");
 	}
 
-#ifdef EMPER_STATS
-	int res = std::atexit(&printLastRuntimeStats);
-	if (res) {
-		DIE_MSG("could not register printStats() with at_exit()");
+	if constexpr (emper::STATS) {
+		int res = std::atexit(&printLastRuntimeStats);
+		if (res) {
+			DIE_MSG("could not register printStats() with at_exit()");
+		}
 	}
-#endif
 }
 
 Runtime::~Runtime() {

emper/strategies/laws/LawsDispatcher.cpp

@@ -2,11 +2,14 @@
 // Copyright © 2020 Florian Schmaus
 #include "LawsDispatcher.hpp"
 
-#include "LawsStrategy.hpp"	 // IWYU pragma: keep
-#include "Runtime.hpp"
-#include "emper-config.h"
+#include <atomic>	 // for atomic, memory_order_relaxed
 
-class Fiber;
+#include "Common.hpp"	 // for DIE_MSG
+#include "Emper.hpp"
+#include "Fiber.hpp"				 // for Fiber
+#include "LawsStrategy.hpp"	 // for LawsStrategy, LawsStrategy::FiberSource
+#include "Runtime.hpp"
+#include "emper-config.h"	 // for EMPER_WORKER_SLEEP
 
 void LawsDispatcher::dispatchLoop() {
 	while (true) {
@@ -24,27 +27,28 @@ void LawsDispatcher::dispatchLoop() {
 		// boolean initialize to true in order to check if this fiber
 		// is runnable.
 		if (isRunnable(fiber)) {
-#ifdef EMPER_STATS
-			LawsStrategy::FiberSource fiberSource =
-					static_cast<LawsStrategy::FiberSource>(fiber->getFlag());
-			switch (fiberSource) {
-				case LawsStrategy::FiberSource::fromPriority:
-					lawsStrategy.dispatchedFiberFromPriority.fetch_add(1, std::memory_order_relaxed);
-					break;
-				case LawsStrategy::FiberSource::fromLocal:
-					lawsStrategy.dispatchedFiberFromLocal.fetch_add(1, std::memory_order_relaxed);
-					break;
-				case LawsStrategy::FiberSource::stolen:
-					lawsStrategy.dispatchedFiberStolen.fetch_add(1, std::memory_order_relaxed);
-					break;
-				case LawsStrategy::FiberSource::mainThread:
-					lawsStrategy.dispatchedFiberFromMainThread.fetch_add(1, std::memory_order_relaxed);
-					break;
-				default:
-					DIE_MSG("Unknown fiber flag: " << flag);
-					break;
+			if constexpr (emper::STATS) {
+				LawsStrategy::FiberSource fiberSource =
+						static_cast<LawsStrategy::FiberSource>(fiber->getFlag());
+				switch (fiberSource) {
+					case LawsStrategy::FiberSource::fromPriority:
+						lawsStrategy.dispatchedFiberFromPriority.fetch_add(1, std::memory_order_relaxed);
+						break;
+					case LawsStrategy::FiberSource::fromLocal:
+						lawsStrategy.dispatchedFiberFromLocal.fetch_add(1, std::memory_order_relaxed);
+						break;
+					case LawsStrategy::FiberSource::stolen:
+						lawsStrategy.dispatchedFiberStolen.fetch_add(1, std::memory_order_relaxed);
+						break;
+					case LawsStrategy::FiberSource::mainThread:
+						lawsStrategy.dispatchedFiberFromMainThread.fetch_add(1, std::memory_order_relaxed);
+						break;
+					default:
+						DIE_MSG("Unknown fiber flag: " << flag);
+						break;
+				}
 			}
-#endif
+
 			// The fiber was marked das runnable. Run it now.
 			dispatch(fiber);
 			// Update the affinity if one was set.

emper/strategies/laws/LawsScheduler.cpp

@@ -2,11 +2,14 @@
 // Copyright © 2020 Florian Schmaus
 #include "LawsScheduler.hpp"
 
+#include <atomic>	 // for atomic, memory_order_relaxed
+
 #include "Common.hpp"
 #include "Debug.hpp"
+#include "Emper.hpp"
 #include "LawsStrategy.hpp"	 // IWYU pragma: keep
 #include "Runtime.hpp"
-#include "emper-config.h"
+#include "emper-config.h"	 // for EMPER_WORKER_SLEEP
 
 #define EMPER_OVERFLOW_QUEUE
 
@@ -47,9 +50,9 @@ void LawsScheduler::schedule(Fiber& fiber) {
 		// We found a fiber to schedule on a remote prority queue.
 		increaseRefCount(fiber);
 		priorityQueues[affinity]->enqueue(&fiber);
-#ifdef EMPER_STATS
-		lawsStrategy.scheduledFibersToRemotePriority.fetch_add(1, std::memory_order_relaxed);
-#endif
+		if constexpr (emper::STATS) {
+			lawsStrategy.scheduledFibersToRemotePriority.fetch_add(1, std::memory_order_relaxed);
+		}
 	}
 
 scheduleToLocalWsQueue:
@@ -61,9 +64,9 @@ scheduleToLocalWsQueue:
 		ABORT("Could not push fiber " << &fiber << " into queue");
 #endif
 	} else {
-#ifdef EMPER_STATS
-		lawsStrategy.scheduledFibersToLocal.fetch_add(1, std::memory_order_relaxed);
-#endif
+		if constexpr (emper::STATS) {
+			lawsStrategy.scheduledFibersToLocal.fetch_add(1, std::memory_order_relaxed);
+		}
 	}
 
 #ifdef EMPER_WORKER_SLEEP
@@ -75,20 +78,22 @@ auto LawsScheduler::nextFiber() -> Fiber* {
 	Fiber* fiber = priorityQueue.dequeue();
 	if (fiber != nullptr) {
 		// We fetched a fiber from your local priority queue.
-#ifdef EMPER_STATS
-		unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::fromPriority);
-		fiber->setFlag(flag);
-#endif
+		if constexpr (emper::STATS) {
+			unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::fromPriority);
+			fiber->setFlag(flag);
+		}
+
 		return fiber;
 	}
 
 	bool poped = queue.popBottom(&fiber);
 
 	if (likely(poped)) {
-#ifdef EMPER_STATS
-		unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::fromLocal);
-		fiber->setFlag(flag);
-#endif
+		if constexpr (emper::STATS) {
+			unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::fromLocal);
+			fiber->setFlag(flag);
+		}
+
 		return fiber;
 	}
 
@@ -100,10 +105,11 @@ auto LawsScheduler::nextFiber() -> Fiber* {
 
 	poped = queues[victim]->popTop(&fiber);
 	if (poped) {
-#ifdef EMPER_STATS
-		unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::stolen);
-		fiber->setFlag(flag);
-#endif
+		if (emper::STATS) {
+			unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::stolen);
+			fiber->setFlag(flag);
+		}
+
 		return fiber;
 	}
 
@@ -112,10 +118,11 @@ auto LawsScheduler::nextFiber() -> Fiber* {
 	// Try the main thread queue to get work as last resort.
 	poped = mainThreadQueue->popTop(&fiber);
 	if (poped) {
-#ifdef EMPER_STATS
-		unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::mainThread);
-		fiber->setFlag(flag);
-#endif
+		if constexpr (emper::STATS) {
+			unsigned int flag = static_cast<unsigned int>(LawsStrategy::FiberSource::mainThread);
+			fiber->setFlag(flag);
+		}
+
 		return fiber;
 	}
 

emper/strategies/ws/WsScheduler.cpp

@@ -2,12 +2,15 @@
 // Copyright © 2020 Florian Schmaus
 #include "WsScheduler.hpp"
 
+#include <atomic>
 #include <ostream>
 
 #include "Common.hpp"
 #include "Debug.hpp"
+#include "Emper.hpp"
 #include "Runtime.hpp"
 #include "emper-config.h"
+#include "strategies/ws/WsStrategy.hpp"
 
 class Fiber;
 
@@ -35,9 +38,9 @@ void WsScheduler::schedule(Fiber& fiber) {
 		ABORT("Could not push fiber " << &fiber << " into queue");
 	}
 
-#ifdef EMPER_STATS
-	wsStrategy.scheduledFibers.fetch_add(1, std::memory_order_relaxed);
-#endif
+	if constexpr (emper::STATS) {
+		wsStrategy.scheduledFibers.fetch_add(1, std::memory_order_relaxed);
+	}
 
 #ifdef EMPER_WORKER_SLEEP
 	notifyRuntimeAboutNewWork();
@@ -49,9 +52,9 @@ auto WsScheduler::nextFiber() -> Fiber* {
 	bool poped = queue.popBottom(&fiber);
 
 	if (likely(poped)) {
-#ifdef EMPER_STATS
-		wsStrategy.nextFiberFromLocal.fetch_add(1, std::memory_order_relaxed);
-#endif
+		if constexpr (emper::STATS) {
+			wsStrategy.nextFiberFromLocal.fetch_add(1, std::memory_order_relaxed);
+		}
 		return fiber;
 	}
 
@@ -66,9 +69,10 @@ auto WsScheduler::nextFiber() -> Fiber* {
 
 		poped = queues[victim]->popTop(&fiber);
 		if (poped) {
-#ifdef EMPER_STATS
-			wsStrategy.nextFiberStolen.fetch_add(1, std::memory_order_relaxed);
-#endif
+			if constexpr (emper::STATS) {
+				wsStrategy.nextFiberStolen.fetch_add(1, std::memory_order_relaxed);
+			}
+
 			return fiber;
 		}
 	}