CPU high due to threads
Beyond a certain point, adding threads does not increase throughput. It increases scheduling overhead and contention.
Evidence to look for
Thread count far exceeds available cores
Context switches per second are abnormally high
CPU rises but throughput plateaus
What it usually means
The CPU is spending time switching between threads rather than executing them. This is scheduling overhead.
What to do next
- 1Reduce thread or worker counts
- 2Use async patterns where possible
- 3Profile to find the optimal concurrency level
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