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load-average.md

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71 lines (50 loc) · 1.92 KB
title Load Average
description Get system load average without needing delta calculations
weight 14

Load Average

Get system load average without needing delta calculations.

Overview

Load average represents the number of processes in the run queue (runnable + waiting for CPU). On Linux, it also includes processes in uninterruptible I/O wait.

use Cbox\SystemMetrics\SystemMetrics;

$load = SystemMetrics::loadAverage()->getValue();

Basic Usage

// Raw load average values
echo "Load (1 min): {$load->oneMinute}\n";
echo "Load (5 min): {$load->fiveMinutes}\n";
echo "Load (15 min): {$load->fifteenMinutes}\n";

Normalized Load (Per-Core Capacity)

$cpu = SystemMetrics::cpu()->getValue();
$normalized = $load->normalized($cpu);

// Normalized values (0.0 to 1.0+ per core)
echo "Normalized (1 min): " . round($normalized->oneMinute, 3) . "\n";

// Percentage helpers (0% to 100%+)
echo "CPU Capacity (1 min): " . round($normalized->oneMinutePercentage(), 1) . "%\n";
echo "CPU Capacity (5 min): " . round($normalized->fiveMinutesPercentage(), 1) . "%\n";
echo "CPU Capacity (15 min): " . round($normalized->fifteenMinutesPercentage(), 1) . "%\n";
echo "Core count: {$normalized->coreCount}\n";

Interpretation

  • < 1.0 (< 100%): System has spare capacity
  • = 1.0 (= 100%): System is at full capacity
  • > 1.0 (> 100%): System is overloaded, processes are queuing

Note: Load average ≠ CPU usage percentage. A system with high I/O wait can have high load but low CPU usage.

Use Cases

Load Monitoring

$load = SystemMetrics::loadAverage()->getValue();
$cpu = SystemMetrics::cpu()->getValue();
$normalized = $load->normalized($cpu);

if ($normalized->oneMinutePercentage() > 80) {
    echo "⚠️ High load: " . round($normalized->oneMinutePercentage(), 1) . "%\n";
}

Related Documentation