There are various tools and technologies available for monitoring system performance. The specific choice of tools depends on the nature of the system, the scale of operations, and the specific metrics or aspects you want to monitor. Here are some commonly used tools and technologies for monitoring system performance:

1. Monitoring Platforms :
   * Prometheus: A widely used open-source monitoring and alerting toolkit with a flexible query language (PromQL).
   * Grafana: A popular open-source platform for visualizing and analyzing metrics from various data sources, including Prometheus.
   * Datadog: A cloud-based monitoring and analytics platform that offers real-time visibility into system performance and metrics.

2. Logging and Log Analysis :
   * ELK Stack (Elasticsearch, Logstash, and Kibana): A popular open-source stack for collecting, processing, and analyzing log data.
   * Splunk: A powerful commercial platform for collecting, indexing, and analyzing machine-generated data, including logs.

3. Infrastructure Monitoring :
   * Nagios: A widely used open-source monitoring system that provides comprehensive monitoring and alerting capabilities.
   * Zabbix: An open-source monitoring solution that offers real-time monitoring, alerting, and visualization of infrastructure components. 4. Application Performance Monitoring (APM) :
   * New Relic: A cloud-based APM platform that provides deep insights into the performance of applications, including code-level analysis and transaction tracing.
   * AppDynamics: A comprehensive APM tool that offers real-time monitoring, performance diagnostics, and end-user experience monitoring.

5. Distributed Tracing :
   * Jaeger: An open-source end-to-end distributed tracing system that helps visualize and analyze transaction traces across microservices.

6. Real User Monitoring (RUM) :
   * Google Analytics: A web analytics tool that provides insights into user behavior, page load times, and other user-centric metrics.

7. Synthetic Monitoring :
   * Pingdom: A cloud-based synthetic monitoring tool that checks the availability and performance of websites and web applications from various locations.

8. Container and Orchestration Monitoring :
   * Kubernetes Dashboard: A web-based interface for visualizing and managing Kubernetes clusters, including monitoring cluster health and resource usage.
   * Prometheus Operator: A Kubernetes-native monitoring and alerting solution that automatically configures Prometheus for monitoring applications running in Kubernetes.