HostContextSwitchingHigh

HostContextSwitchingHigh #

Context switching is growing on the node (twice the daily average during the last 15m)

Alert Rule
alert: HostContextSwitchingHigh
annotations:
  description: |-
    Context switching is growing on the node (twice the daily average during the last 15m)
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/node-exporter/hostcontextswitchinghigh/
  summary: Host context switching high (instance {{ $labels.instance }})
expr: '(rate(node_context_switches_total[15m])/count without(mode,cpu) (node_cpu_seconds_total{mode="idle"}))
  / (rate(node_context_switches_total[1d])/count without(mode,cpu) (node_cpu_seconds_total{mode="idle"}))
  > 2 '
for: 0m
labels:
  severity: warning

Meaning #

The HostContextSwitchingHigh alert is triggered when the rate of context switching on a host exceeds twice the daily average during the last 15 minutes. Context switching is a performance metric that measures the number of times the CPU switches between different processes or threads. High context switching rates can indicate system overload, inefficient resource utilization, or other performance-related issues.

Impact #

A high context switching rate can have significant performance implications for the affected host, including:

  • Decreased system responsiveness and increased latency
  • Increased CPU usage and potential overheating
  • Reduced throughput and overall system efficiency
  • Potential impact on dependent services and applications

Diagnosis #

To diagnose the root cause of the high context switching rate, follow these steps:

  1. Check system logs: Review system logs for errors, warnings, or other indications of system overload or misconfiguration.
  2. Investigate CPU usage: Analyze CPU usage patterns to identify processes or threads that may be contributing to the high context switching rate.
  3. Verify system configuration: Check system configuration files and settings to ensure they are properly configured and optimized for performance.
  4. Monitor system resources: Closely monitor system resources such as memory, disk I/O, and network utilization to identify potential bottlenecks.

Mitigation #

To mitigate the high context switching rate, consider the following steps:

  1. Adjust system configuration: Tune system configuration settings to optimize performance and reduce context switching.
  2. Implement resource limiting: Implement resource limiting measures such as cgroups or ulimits to prevent rogue processes from consuming excessive system resources.
  3. Optimize system resources: Optimize system resources such as memory, disk I/O, and network utilization to reduce contention and bottlenecks.
  4. Upgrade system resources: Consider upgrading system resources such as CPU, memory, or storage to improve overall system performance.

Remember to consult the Node Exporter documentation for more detailed guidance on troubleshooting and resolving high context switching rates.

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