▼ |  | Futures Visualizer

1 | Execution Timeline
2 | Future Creation Tree
3 | Futures Tracing

On this page:

Futures Visualizer
visualize-futures
visualize-futures-thunk
show-visualizer

7.2
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## Futures Visualizer

> > > Parallelism with Futures in The Racket Guide introduces

(require future-visualizer) | package: future-visualizer

The futures visualizer is a graphical profiling tool for parallel programs written using future. The tool shows a timeline of a program’s execution including all future-related events, as well as the overall amount of processor utilization at any point during the program’s lifetime.

> syntax (visualize-futures e ...)
> procedure (visualize-futures-thunk thunk) → any
> thunk : (-> any)

The visualize-futures macro enables the collection of data required by the visualizer and displays a profiler window showing the corresponding trace. The visualize-futures-thunk provides similar functionality where program code is contained within thunk.

A typical program using profiling might look like the following:

> (require racket/future
> future-visualizer)
> (visualize-futures
> (let ([f (future (lambda () ...))])
> ...
> (touch f)))

The preceding program is equivalent to:

> (require racket/future
> future-visualizer/trace
> future-visualizer)
> (start-future-tracing!)
> (let ([f (future (lambda () ...))])
> ...
> (touch f))
> (stop-future-tracing!)
> (show-visualizer)

> procedure (show-visualizer #:timeline timeline) → void?
> timeline : (listof indexed-future-event?)

Displays the visualizer window. If the function is called with no arguments, it must be preceded by the following sequence: a call to start-future-tracing!, program code that is being traced, and a call to stop-future-tracing! – in which case the visualizer will show data for all events logged in between those calls (via timeline-events). Note that visualize-futures and visualize-futures-thunk are simpler alternatives to using these primitives directly. The timeline argument can be used to show the visualizer for a previously-generated trace.
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