Understanding Resident Memory Usage in Linux, Windows, and macOS
In this article, we will dive deep into the topic of resident memory usage in Linux, Windows, and macOS. Resident memory usage, also referred to as resident set size (RSS), denotes the amount of physical memory a process has in its address space.
How to check Resident Memory Usage
To monitor the resident memory usage of processes, various tools are available on each operating system. In Linux, you can use the htop, top, and free commands, as well as the /proc file system.
# htop
# top
# free -m
On Windows, you can use the Task Manager or the more powerful Process Explorer by Sysinternals. For macOS, Activity Monitor is the built-in utility to check process memory usage.
Resident Memory Usage in Linux
htop and top are two popular tools to display process information in Linux. They both provide real-time updates of process memory usage. When interpreting the output, it is important to understand the memory columns, such as RES in top and Memory in htop.
# top
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1234 user 20 0 1234567 345678 23456 S 0.0 3.3 0:01.24 myprocess
The RES column in the above output shows the resident memory usage of the process in kilobytes. In htop, the Memory column (the next column after RES) displays the same information in a more human-readable format.
# htop
PID USER PRI NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1234 user 20 0 1.2G 333M 234M S 0.0 10.7 0:01.24 myprocessResident Memory Usage in Windows
In Windows, the Task Manager provides an easy way to monitor process memory usage through the Memory column, but it is essential to understand the different memory values presented:
- Working Set: The current amount of physical memory a process has allocated.
- Working Set - Private: The amount of physical memory that is not shared with other processes.
- Peak Working Set: The maximum amount of physical memory a process has allocated since it was started.
In Task Manager, ensure you are looking at the Working Set value to determine the current resident memory usage.
Resident Memory Usage in macOS
In macOS, Activity Monitor displays the memory usage in the Real Mem column, measured in kilobytes. Similar to Linux, this value represents the amount of physical memory a process has allocated.
Understanding resident memory usage is crucial when optimizing and troubleshooting applications' performance issues. In this article, we have covered the key concepts, methods, and tools for checking resident memory usage in Linux, Windows, and macOS.