Why does ext4 perform periodic cpu-based work, and how can these cpu interruptions be minimized

Solution Unverified - Updated -


  • Systems with ext4 filesystems periodically interrupt cpu-based workloads to perform filesystem-related maintenance functions. This can sometimes result in undesirable cpu latencies for high-performance, latency-sensitive user applications. What background work is being performed in the filesystem code, and how can these latencies be reduced and/or eliminated?

  • In particular, relatively large cpu spikes have been observed at approximately 30-second intervals.

  • Smaller spikes are also observed at 25ms intervals.


  • RHEL 6
  • ext4 filesystems
  • latency-sensitive applications executing on isolated cpus

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