Log the actual sizes of the thread pools

If one don't try to specify the actual number of threads in
the thread pool one used to get a line saying that each
thread pool was of size 0.

Delay logging the size of the pools until we've started
the thread pool and know the sizes as this saves us from
guessing/calculating the actual thread pool sizes

Change-Id: I3b99088e87e3ffccea0cb4dad23201b19d9318cb
Reviewed-on: https://review.couchbase.org/c/kv_engine/+/190399
Tested-by: Build Bot <[email protected]>
Reviewed-by: Dave Rigby <[email protected]>

Author: trondn

daemon/memcached.cc

@@ -648,14 +648,6 @@ static void initialize_sasl() {
 static void startExecutorPool() {
     auto& settings = Settings::instance();
 
-    LOG_INFO(
-            "Start executor pool with backend:Folly readers:{} writers:{} "
-            "auxIO:{} nonIO:{}",
-            settings.getNumReaderThreads(),
-            settings.getNumWriterThreads(),
-            settings.getNumAuxIoThreads(),
-            settings.getNumNonIoThreads());
-
     ExecutorPool::create(
             ExecutorPool::Backend::Folly,
             0,
@@ -666,6 +658,16 @@ static void startExecutorPool() {
     ExecutorPool::get()->registerTaskable(NoBucketTaskable::instance());
     ExecutorPool::get()->setDefaultTaskable(NoBucketTaskable::instance());
 
+    auto* pool = ExecutorPool::get();
+    LOG_INFO(
+            "Started executor pool with backend:{} readers:{} "
+            "writers:{} auxIO:{} nonIO:{}",
+            pool->getName(),
+            pool->getNumReaders(),
+            pool->getNumWriters(),
+            pool->getNumAuxIO(),
+            pool->getNumNonIO());
+
     // MB-47484 Set up the settings callback for the executor pool now that
     // it is up'n'running
     settings.addChangeListener(

executor/cb3_executorpool.h

@@ -177,6 +177,10 @@ class CB3ExecutorPool : public ExecutorPool {
 
     size_t getNumNonIO() override;
 
+    std::string_view getName() const override {
+        return "CB3";
+    }
+
     void setNumReaders(ThreadPoolConfig::ThreadCount v) override {
         adjustWorkers(READER_TASK_IDX, calcNumReaders(v));
     }

executor/executorpool.h

@@ -102,6 +102,9 @@ class ExecutorPool {
     /// @returns the number of Tasks ready to run.
     virtual size_t getNumReadyTasks() = 0;
 
+    /// @returns the name of the executor pool backed
+    virtual std::string_view getName() const = 0;
+
     /***************** Task Ownership ***************************************/
 
     /**

executor/folly_executorpool.h

@@ -168,6 +168,9 @@ class FollyExecutorPool : public ExecutorPool {
     void setNumNonIO(uint16_t v) override;
     size_t getNumSleepers() override;
     size_t getNumReadyTasks() override;
+    std::string_view getName() const override {
+        return "Folly";
+    }
 
     void registerTaskable(Taskable& taskable) override;
     void unregisterTaskable(Taskable& taskable, bool force) override;