foundationdb/fdbrpc/Stats.actor.cpp

112 lines
3.2 KiB
C++

/*
* Stats.actor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "fdbrpc/Stats.h"
#include "flow/actorcompiler.h" // has to be last include
Counter::Counter(std::string const& name, CounterCollection& collection)
: name(name), interval_start(0), last_event(0), interval_sq_time(0), interval_start_value(0), interval_delta(0), roughness_interval_start(0)
{
metric.init(collection.name + "." + (char)toupper(name.at(0)) + name.substr(1), collection.id);
collection.counters.push_back(this);
}
void Counter::operator += (Value delta) {
if (!delta) return; //< Otherwise last_event will be reset
interval_delta += delta;
auto t = now();
auto elapsed = t - last_event;
interval_sq_time += elapsed * elapsed;
last_event = t;
metric += delta;
}
double Counter::getRate() const {
double elapsed = now() - interval_start;
return elapsed > 0 ? interval_delta / elapsed : 0;
}
double Counter::getRoughness() const {
double elapsed = now() - roughness_interval_start;
if(elapsed == 0) {
return -1;
}
// If we have time interval samples t in T, and let:
// n = size(T) = interval_delta
// m = mean(T) = elapsed / interval_delta
// v = sum(t^2) for t in T = interval_sq_time
//
// The formula below is: (v/(m*n)) / m - 1
// This is equivalent to (v/n - m^2) / m^2 = Variance(T)/m^2
// Variance(T)/m^2 is equal to Variance(t/m) for t in T
double delay = interval_sq_time / elapsed;
return delay * interval_delta / elapsed - 1;
}
void Counter::resetInterval() {
interval_start_value += interval_delta;
interval_delta = 0;
interval_sq_time = 0;
interval_start = now();
if(last_event == 0) {
last_event = interval_start;
}
roughness_interval_start = last_event;
}
void Counter::clear() {
resetInterval();
interval_start_value = 0;
metric = 0;
}
void CounterCollection::logToTraceEvent(TraceEvent &te) const {
for (ICounter* c : counters) {
te.detail(c->getName().c_str(), c);
c->resetInterval();
}
}
ACTOR Future<Void> traceCounters(std::string traceEventName, UID traceEventID, double interval, CounterCollection* counters, std::string trackLatestName) {
wait(delay(0)); // Give an opportunity for all members used in special counters to be initialized
for (ICounter* c : counters->counters)
c->resetInterval();
state double last_interval = now();
loop{
TraceEvent te(traceEventName.c_str(), traceEventID);
te.detail("Elapsed", now() - last_interval);
counters->logToTraceEvent(te);
if (!trackLatestName.empty()) {
te.trackLatest(trackLatestName);
}
last_interval = now();
wait(delay(interval, TaskPriority::FlushTrace));
}
}