CPU time
CPU time is the amount of processor execution time consumed by a program, process, thread, or computation.
Experimentation for Engineers
CPU time is the amount of processor execution time consumed by a program or process.
- How it is used
- Uses CPU time as the metric minimized while tuning JIT parameters for web-server request handling.
- How deep it goes
- Works through noisy offline measurement, response-surface estimation, Gaussian process regression, and an iterative stopping rule.
- Examples
- Uses production request-log replay, a Python JIT-plus-server simulator, and measurements at parameters 0.5 and 0.0.
- What you can do after
- Apply it via Bayesian optimization to compare JIT configurations and stop when CPU-time measurements stabilize.
Troubleshooting Java, Second Edition
CPU time is the amount of processor time a method or operation actively spends executing instructions.
- How it is used
- Uses CPU time with execution time to investigate latency and distinguish computation from waiting.
- How deep it goes
- Explains the metric through profiler observations and contrasts it with execution time, stopping short of measurement internals.
- Examples
- Uses a five-second /demo HTTP delay where getResponseCode() spends execution time waiting with zero CPU time.
- What you can do after
- Diagnose latency by comparing CPU time with execution time in profiler stacks.
Read how Troubleshooting Java, Second Edition explains CPU time →
Automating API Delivery
Task time, or touch time, is the time during which work is actively performed on a process task, excluding waiting and interruptions.
- How it is used
- Tracks active effort at process steps during process improvement, alongside lead time and output-quality measures.
- How deep it goes
- Defines included and excluded time, distinguishes task time from lead time, and shows how to record it in a process map.
- Examples
- Uses Acme’s API design and review process and Jira tickets awaiting processing as examples.
- What you can do after
- Evaluate process steps by recording task time and lead time in a process map and time ladder.
Apache Kafka in Action
CPU time is the amount of processor execution time consumed by a client's requests on a broker.
- How it is used
- Protects brokers from client-driven overload by limiting request-processing capacity.
- How deep it goes
- Defines broker and thread-based enforcement, explains limitations, and demonstrates default, client-specific, and user-specific quotas.
- Examples
- Uses online-shop defaults, a newsletter producer restriction, a warehouse consumer allowance, and a network/I/O thread formula.
- What you can do after
- Operate/configure Kafka quotas that reserve request capacity and reduce overload risk for selected clients or users.
Related concepts
- timestampcontrasts with · A timestamp is a value representing a specific point in time, typically associated with an event, observation, or data item.
- meancontrasts with · A mean is a measure of central tendency, calculated as the arithmetic average of values or, for a random variable, as the probability-weighted average of its possible values.
- lead timecontrasts with · Lead time is the elapsed time from the initiation, request, or availability of work until its completion or delivery.
- experimentationmeasured by · Experimentation is the deliberate testing of an idea, intervention, or alternative by observing outcomes to gather evidence or compare effects.
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