Context switching and high CPU
Context switches are when the CPU saves one task's state and loads another's. Some switching is normal, but excessive rates waste CPU.
Evidence to look for
Context switches per second exceed 50,000+ on a busy server
CPU is high but throughput is stagnant
Reducing threads improves performance
What it usually means
Each context switch has a cost: saving registers, flushing caches, loading new state. At high rates, this overhead becomes significant.
What to do next
- 1Reduce thread or process counts
- 2Pin critical threads to specific cores
- 3Use async IO instead of thread-per-connection
See what's causing your CPU
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