From 13553e1a07db0ea97cf2f44f5ec886eec776df1a Mon Sep 17 00:00:00 2001
From: flamingcow <flamingcow@gmail.com>
Date: Fri, 10 May 2019 23:04:26 -0700
Subject: [PATCH] Working getrusage and wall clock metrics

---
 .gitignore      |  1 +
 Makefile        |  7 +++++--
 example_loop.cc | 22 ++++++++++++++++++++
 usage.cc        | 53 +++++++++++++++++++++++++++++++++++++++++++++++--
 usage.h         | 18 +++++++++++++++--
 5 files changed, 95 insertions(+), 6 deletions(-)
 create mode 100644 example_loop.cc

diff --git a/.gitignore b/.gitignore
index d0bc775..f823577 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *.a
 *.o
 *.so
+example_loop
diff --git a/Makefile b/Makefile
index cf5cc10..a55b1a0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,9 @@
 FIRE_CXX ?= clang++
 FIRE_CXXFLAGS ?= -O3 -std=gnu++2a -Wall -Werror -Wextra -fPIE -fPIC -fstack-protector-strong -fsanitize=safe-stack -fsanitize=safe-stack
 FIRE_LDFLAGS ?= -fuse-ld=gold -flto -Wl,-z,relro -Wl,-z,now
-FIRE_LDLIBS ?= -lglog
+FIRE_LDLIBS ?= -lgflags -lglog
 
-all: fireusage.a fireusage.o fireusage.so
+all: fireusage.a fireusage.o fireusage.so example_loop
 
 objects = usage.o
 
@@ -16,6 +16,9 @@ fireusage.o: $(objects)
 fireusage.so: $(objects)
 	$(FIRE_CXX) $(FIRE_CXXFLAGS) $(FIRE_LDFLAGS) -shared -o $@ $+ $(FIRE_LDFLIBS)
 
+example_loop: example_loop.o fireusage.o
+	$(FIRE_CXX) $(FIRE_CXXFLAGS) $(FIRE_LDFLAGS) -pie -o $@ $+ $(FIRE_LDLIBS)
+
 %.o: %.cc *.h Makefile
 	$(FIRE_CXX) $(FIRE_CXXFLAGS) -c -o $@ $<
 
diff --git a/example_loop.cc b/example_loop.cc
new file mode 100644
index 0000000..48bb949
--- /dev/null
+++ b/example_loop.cc
@@ -0,0 +1,22 @@
+#include <gflags/gflags.h>
+#include <glog/logging.h>
+
+#include "usage.h"
+
+int main(int argc, char *argv[]) {
+	google::InitGoogleLogging(argv[0]);
+	gflags::ParseCommandLineFlags(&argc, &argv, true);
+
+	fireusage::UsageTracker tracker;
+	tracker.Start();
+	for (int i = 0; i < 100000000; ++i) {
+		tracker.AddEvent();
+		for (int _ = 0; _ < 100000; ++_) {
+		}
+	}
+	tracker.Stop();
+	tracker.Log();
+
+	gflags::ShutDownCommandLineFlags();
+	google::ShutdownGoogleLogging();
+}
diff --git a/usage.cc b/usage.cc
index 4d218ef..a146b43 100644
--- a/usage.cc
+++ b/usage.cc
@@ -1,9 +1,58 @@
+#include <glog/logging.h>
+#include <iomanip>
+
 #include "usage.h"
 
 namespace fireusage {
 
-UsageTracker::UsageTracker(const std::string_view& plural_resource_name)
-	: plural_resource_name_(plural_resource_name) {
+namespace {
+
+std::chrono::nanoseconds TvToNs(const timeval& tv) {
+	return std::chrono::seconds(tv.tv_sec) + std::chrono::microseconds(tv.tv_usec);
+	
+}
+
+} // namespace
+
+void UsageTracker::AddEvents(uint64_t num) {
+	events_ += num;
+}
+
+void UsageTracker::AddEvent() {
+	events_ += 1;
+}
+
+void UsageTracker::Start() {
+	CHECK(!running_);
+	running_ = true;
+
+	PCHECK(getrusage(RUSAGE_THREAD, &start_usage_) == 0);
+	start_time_ = std::chrono::steady_clock::now();
+}
+
+void UsageTracker::Stop() {
+	CHECK(running_);
+	running_ = false;
+
+	const auto end_time_ = std::chrono::steady_clock::now();
+
+	rusage end_usage_;
+	PCHECK(getrusage(RUSAGE_THREAD, &end_usage_) == 0);
+
+	wall_time_ += end_time_ - start_time_;
+	user_time_ += TvToNs(end_usage_.ru_utime) - TvToNs(start_usage_.ru_utime);
+	sys_time_ += TvToNs(end_usage_.ru_stime) - TvToNs(start_usage_.ru_stime);
+}
+
+void UsageTracker::Log() {
+	LOG(INFO) << "usage:";
+	LOG(INFO) << "\tevents:            " << std::setw(20) << std::setfill(' ') << events_;
+	LOG(INFO) << "\twall time:         " << std::setw(20) << std::setfill(' ') << wall_time_.count() << "ns";
+	LOG(INFO) << "\tuser time:         " << std::setw(20) << std::setfill(' ') << user_time_.count() << "ns";
+	LOG(INFO) << "\tsys time:          " << std::setw(20) << std::setfill(' ') << sys_time_.count() << "ns";
+	LOG(INFO) << "\twall time / event: " << std::setw(20) << std::setfill(' ') << (wall_time_ / events_).count() << "ns";
+	LOG(INFO) << "\tuser time / event: " << std::setw(20) << std::setfill(' ') << (user_time_ / events_).count() << "ns";
+	LOG(INFO) << "\tsys time / event:  " << std::setw(20) << std::setfill(' ') << (sys_time_ / events_).count() << "ns";
 }
 
 } // namespace fireusage
diff --git a/usage.h b/usage.h
index 6291e3b..9f554a0 100644
--- a/usage.h
+++ b/usage.h
@@ -1,15 +1,29 @@
 #pragma once
 
+#include <chrono>
 #include <string>
+#include <sys/resource.h>
 
 namespace fireusage {
 
 class UsageTracker {
   public:
-	UsageTracker(const std::string_view& plural_resource_name);
+	void AddEvents(uint64_t num);
+	void AddEvent();
+
+	void Start();
+	void Stop();
+	void Log();
 
   private:
-	const std::string plural_resource_name_;
+	bool running_ = false;
+	uint64_t events_ = 0;
+	std::chrono::nanoseconds wall_time_;
+	std::chrono::nanoseconds user_time_;
+	std::chrono::nanoseconds sys_time_;
+
+	std::chrono::steady_clock::time_point start_time_;
+	rusage start_usage_;
 };
 
 } // namespace fireusage