https://github.com/holmanb/psimon
CLI tool that allows interactive monitoring of Linux kernel Pressure Stall Information, a feature in Linux 4.20 and beyond
https://github.com/holmanb/psimon
psi
Last synced: over 1 year ago
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CLI tool that allows interactive monitoring of Linux kernel Pressure Stall Information, a feature in Linux 4.20 and beyond
- Host: GitHub
- URL: https://github.com/holmanb/psimon
- Owner: holmanb
- Created: 2020-12-14T02:42:14.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2021-12-07T21:09:21.000Z (over 4 years ago)
- Last Synced: 2025-01-20T06:19:00.770Z (over 1 year ago)
- Topics: psi
- Language: C
- Homepage:
- Size: 76.2 KB
- Stars: 4
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# psimon
monitoring utility for pressure stall information
# What is Pressure Stall Information?
>The psi feature identifies and quantifies the disruptions caused by resource contention and the time impact it has on complex workloads or even entire systems.
## Can't We Already Get Interactive System Load Information?
PSI reports the percentage of wallclock time in which tasks are waiting for a CPU to run on.
This is more granular and indicitave of system health than system load [3].
## Runtime Requirements
Kernel must support psi (must be built with `CONFIG_PSI=y`), which requires at least linux 4.20
If your kernel is compiled with `CONFIG_PSI_DEFAULT_DISABLED`, you will need to pass a command line flag to pass `psi=1` to the kernel on boot.
## Build Requirements
```
git gcc make
```
## Build Instructions
```
git clone --recurse-submodules https://github.com/holmanb/psimon.git
cd psimon
make
make psimon
```
## Usage
currently `psimon` doesn't require any arguments and shows PSI counter values in realtime
## Future Work
- add cgroup support
- parse "full" pressure counters for io && memory
- add flags for selecting memory, io, or cpu
- randomized file names in /tmp
- various TODO cleanup items in codebase
- add units
- add averages
- fix y axis color issue (see )
## Pressure Stall Information References
[1] Kernel Docs at [kernel.org](https://www.kernel.org/doc/html/latest/accounting/psi.html)
[2] Kernel Source [Docs](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/accounting/psi.rst)
[3] Description At [lwn.net](https://lwn.net/ml/cgroups/20180712172942.10094-1-hannes@cmpxchg.org/)
[4] Facebook Helped Develop [PSI](https://facebookmicrosites.github.io/psi/docs/overview) and includes their use cases