metrics_base.h

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// BSD 3-Clause License
// Copyright (c) 2024, 🍀☀🌕🌥 🌊
// See the LICENSE file in the project root for full license information.
 
#pragma once
 
 // end of metrics
 
#include <atomic>
#include <cstdint>
 
namespace kcenon::thread::metrics {
 
struct BaseSnapshot {
    std::uint64_t tasks_submitted{0};
 
    std::uint64_t tasks_executed{0};
 
    std::uint64_t tasks_failed{0};
 
    std::uint64_t total_busy_time_ns{0};
 
    std::uint64_t total_idle_time_ns{0};
};
 
class MetricsBase {
public:
    virtual ~MetricsBase() = default;
 
    // =========================================================================
    // Recording Methods
    // =========================================================================
 
    void record_submission(std::size_t count = 1) {
        tasks_submitted_.fetch_add(count, std::memory_order_relaxed);
    }
 
    void record_execution(std::uint64_t duration_ns, bool success) {
        if (success) {
            tasks_executed_.fetch_add(1, std::memory_order_relaxed);
        } else {
            tasks_failed_.fetch_add(1, std::memory_order_relaxed);
        }
        total_busy_time_ns_.fetch_add(duration_ns, std::memory_order_relaxed);
    }
 
    void record_idle_time(std::uint64_t duration_ns) {
        total_idle_time_ns_.fetch_add(duration_ns, std::memory_order_relaxed);
    }
 
    virtual void reset() {
        tasks_submitted_.store(0, std::memory_order_relaxed);
        tasks_executed_.store(0, std::memory_order_relaxed);
        tasks_failed_.store(0, std::memory_order_relaxed);
        total_busy_time_ns_.store(0, std::memory_order_relaxed);
        total_idle_time_ns_.store(0, std::memory_order_relaxed);
    }
 
    // =========================================================================
    // Query Methods
    // =========================================================================
 
    [[nodiscard]] std::uint64_t tasks_submitted() const {
        return tasks_submitted_.load(std::memory_order_relaxed);
    }
 
    [[nodiscard]] std::uint64_t tasks_executed() const {
        return tasks_executed_.load(std::memory_order_relaxed);
    }
 
    [[nodiscard]] std::uint64_t tasks_failed() const {
        return tasks_failed_.load(std::memory_order_relaxed);
    }
 
    [[nodiscard]] std::uint64_t total_busy_time_ns() const {
        return total_busy_time_ns_.load(std::memory_order_relaxed);
    }
 
    [[nodiscard]] std::uint64_t total_idle_time_ns() const {
        return total_idle_time_ns_.load(std::memory_order_relaxed);
    }
 
    [[nodiscard]] BaseSnapshot base_snapshot() const {
        return BaseSnapshot{
            tasks_submitted_.load(std::memory_order_relaxed),
            tasks_executed_.load(std::memory_order_relaxed),
            tasks_failed_.load(std::memory_order_relaxed),
            total_busy_time_ns_.load(std::memory_order_relaxed),
            total_idle_time_ns_.load(std::memory_order_relaxed),
        };
    }
 
    [[nodiscard]] double utilization() const {
        const auto busy = total_busy_time_ns_.load(std::memory_order_relaxed);
        const auto idle = total_idle_time_ns_.load(std::memory_order_relaxed);
        const auto total = busy + idle;
        return (total > 0) ? static_cast<double>(busy) / static_cast<double>(total) : 0.0;
    }
 
    [[nodiscard]] double success_rate() const {
        const auto executed = tasks_executed_.load(std::memory_order_relaxed);
        const auto failed = tasks_failed_.load(std::memory_order_relaxed);
        const auto total = executed + failed;
        return (total > 0) ? static_cast<double>(executed) / static_cast<double>(total) : 1.0;
    }
 
protected:
    MetricsBase() = default;
 
    MetricsBase(const MetricsBase&) = delete;
 
    MetricsBase& operator=(const MetricsBase&) = delete;
 
    MetricsBase(MetricsBase&&) = delete;
 
    MetricsBase& operator=(MetricsBase&&) = delete;
 
    // =========================================================================
    // Protected Members (accessible to derived classes)
    // =========================================================================
 
    std::atomic<std::uint64_t> tasks_submitted_{0};
 
    std::atomic<std::uint64_t> tasks_executed_{0};
 
    std::atomic<std::uint64_t> tasks_failed_{0};
 
    std::atomic<std::uint64_t> total_busy_time_ns_{0};
 
    std::atomic<std::uint64_t> total_idle_time_ns_{0};
};
 
} // namespace kcenon::thread::metrics