المدربCPU steal time is the time a virtual CPU was ready to run but the hypervisor ran something else on the physical CPU; Linux reports it as “involuntary wait”. A noisy neighbour is another tenant of the same physical server or network whose load takes resources (CPU, cache, memory bandwidth, network queues) from a customer’s machine and so adds delay to it.
| Case | p50 | p90 | p99 | p99.9 | p99.99 |
|---|---|---|---|---|---|
| Same zone (published) | 270 | – | 395 | – | 760 |
| Same zone (model) | 270 | 333 | 396 | 463 | 743 |
| Cross zone (published) | 555 | – | 755 | – | 1 905 |
| Cross zone (model) | 555 | 657 | 755 | 851 | 1 908 |
| Shared host, noisy neighbour (model) | 270 | 333 | 400 | 7 474 | 13 940 |
firm.cloudplan fits to it; the noisy-neighbour case is an assumption. Data: nw_cloud.percentiles().
fig_cloud.py.