Скачать или смотреть How to Count the Number of Executed Instructions in a Process Including Its Child Processes

Discover how to effectively count executed instructions for a Node.js application running in Docker, including child processes. Learn about using `perf` and `pgrep` commands for accurate performance measurement.
---
This video is based on the question https://stackoverflow.com/q/62851367/ asked by the user 'Michel Gokan Khan' ( https://stackoverflow.com/u/169545/ ) and on the answer https://stackoverflow.com/a/63577216/ provided by the user 'Iduoad' ( https://stackoverflow.com/u/7554715/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to count number of executed instructions of a process id including child processes

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Count the Number of Executed Instructions in a Process Including Its Child Processes

In the world of performance tuning, knowing the number of executed instructions in your application can provide insights about its efficiency. If you are running a Node.js application in a Docker container and want to measure the performance metrics, specifically the executed instructions, you might run into issues when those instructions stem from child processes. This guide discusses a method to get that information accurately.

The Challenge

The problem arises when you’re trying to count the executed instructions for your main Node.js process deployed in Docker. While using the perf command produces results for your primary process, it might not account for the instructions executed by its child processes. This can lead to an incomplete picture of your application's performance.

For example, say you find the PID (Process ID) of your Node.js application and run:

[[See Video to Reveal this Text or Code Snippet]]

This command will monitor the specified process, including metrics like executed instructions and cycles, but will not capture the metrics from child processes.

A Better Approach to Capture All Executed Instructions

To effectively count the executed instructions for a process along with all its child processes, you can utilize the pgrep command. Below is a comprehensive guide on how to do this.

Step 1: Get the Parent PID

First, you need to find the PID of your parent process (e.g., your Node.js server). This can typically be done using commands like pstree:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Use pgrep to Find Child PIDs

You can obtain all the child PIDs belonging to the parent PID with the following command:

[[See Video to Reveal this Text or Code Snippet]]

--ns: This option allows you to retrieve processes running in the same namespace as the specified PID.

Step 3: Format the PIDs for perf

Once you have the PIDs, you need to format them into a comma-separated list. The paste command can help here:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Run perf with All PIDs

Now that you have the complete list of PIDs, you can run the perf command again, but this time include the child processes:

[[See Video to Reveal this Text or Code Snippet]]

Benefits of This Approach

Comprehensive Metrics: By including child processes, you gain a complete understanding of how your application performs under load.

Ease of Use: You automate PID collection and formatting, which saves manual effort.

Linux Compatibility: Works smoothly on Linux systems, making it ideal for developers deploying applications in Docker containers.

Conclusion

By utilizing the combination of pgrep --ns, paste, and perf, you can effectively gather performance metrics for your Node.js application, including all executed instructions from child processes. This method ensures a more accurate representation of your application's performance, allowing for better optimization and troubleshooting.

If you're facing similar challenges, give this approach a try, and take a step closer to better understanding and optimizing your application's performance!