ActivityMonitor - Parallel pool activity monitor - MATLAB (original) (raw)

Parallel pool activity monitor

Since R2025a

Description

Use ActivityMonitor to monitor and collect data on worker activity in a parallel pool.

Monitoring data includes:

• The type of parallel construct, such as parfor,parfeval, and spmd.
• The amount of data (in bytes) the client and workers send and receive.
• The time each worker spends processing their portion of the parallel code.

You can retrieve the monitoring results using the results function and view the monitoring data in the Pool Dashboard.

Creation

Syntax

Description

[monitor](#mw%5F541cb048-1544-4527-83b2-673734e969c1) = parallel.pool.ActivityMonitor creates an ActivityMonitor object and starts collecting activity monitoring data on the current parallel pool. If no parallel pool exists,parallel.pool.ActivityMonitor starts a new parallel pool using the default profile, unless you disable automatic pool creation in your parallel settings.

To save monitoring results, use the results function. To stop collecting and save monitoring results, use the stop function.

example

[monitor](#mw%5F541cb048-1544-4527-83b2-673734e969c1) = parallel.pool.ActivityMonitor([pool](#mw%5Ff9d55cda-effb-43d0-836b-f87a4057cf10)) starts collecting activity monitoring data on the parallel pool specified bypool.

example

[monitor](#mw%5F541cb048-1544-4527-83b2-673734e969c1) = parallel.pool.ActivityMonitor(___,`Start=false`) creates an ActivityMonitor object but does not start collecting activity monitoring data. To start collecting monitoring data, use the start function.

example

Input Arguments

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Parallel pool, specified as a parallel.Pool.ProcessPool orparallel.pool.ClusterPool object.

You can use an interactive or batch parallel pool. ActivityMonitor is not supported on parallel pools of thread workers.

Example: parpool("Processes");

Example: batch(...,Pool=4);

Output Arguments

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Pool activity monitor, returned as an ActivityMonitor object.

Object Functions

Examples

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Create an ActivityMonitor object to start collecting pool monitoring data. With default settings, parallel.pool.ActivityMonitor automatically starts an interactive parallel pool using the default profile if one does not exist.

monitor = parallel.pool.ActivityMonitor;

Starting parallel pool (parpool) using the 'Processes' profile ... Connected to parallel pool with 6 workers.

Run a parfor-loop to generate random numbers and store them in an array.

data = zeros(1,100); parfor idx = 1:100 data(idx) = rand; end

Stop the activity monitor and retrieve the results collected during the parfor execution.

monitorResults = stop(monitor);

Create a parallel pool using the cluster profile,MyCluster.

pool = parpool("MyCluster");

Create an ActivityMonitor object to collect monitoring data for the pool but do not start collecting data immediately.

monitor = parallel.pool.ActivityMonitor(pool,Start=false);

Collect activity monitoring data on a batch pool job using an ActivityMonitor object.

Write a function that creates an ActivityMonitor object to collect monitoring data, executes parallel tasks, and collects pool monitoring results.

function monitorResults = myParallelCode

monitor = parallel.pool.ActivityMonitor;

f(1:100) = parallel.FevalFuture; for idx = 1:100 f(idx) = parfeval(@(n) real(eig(randn(n))),1,5e2); end maxFuture = afterEach(f,@max,1); wait(maxFuture);

monitorResults = stop(monitor); end

Run the myParallelCode function as a batch pool job using the myCluster profile and wait for the batch job to complete.

j = batch(@myParallelCode,1,Pool=4,Profile="myCluster"); wait(j);

Fetch the monitoring results from the completed batch job.

out = fetchOutputs(j); monitoringResults = out{1};

Limitations

• ActivityMonitor is not supported on parallel pools of thread workers.

Alternative Functionality

Tool

You can use the Pool Dashboard to collect and view pool monitoring data on an interactive parallel pool.

Version History

Introduced in R2025a