feeze

Interactive graphical thread and scheduling analysis tool using eBPF.

Goal

The goal of feeze is to provide an easy-to-use interactive tool to analyze performance related to scheduling of threads. The focus is on real-time behavior, i.e., finding reasons performance outliers and fixing these, but this can also help to improve general throughput.

Name feeze

The name was chosen for its Scots meaning to untwist; to unravel, as the end of a thread or rope, which is what the tool is supposed to do with the threads running on your system.

Definition of feeze by wiktionary

Etymology 3

From Scots feeze, from Old Scots fize (“screw”, noun), from Dutch vijs (“screw”), from Middle Dutch vise (“screw, windlass, winch”), from Old French vis, viz (“vise, vice”), from Latin vītis (“vine”). Doublet of vice, vise and withe.

Verb

feeze (third-person singular simple present feezes, present participle feezing, simple past and past participle feezed) (Scotland)

1. (transitive, also with off, on, up) To twist or turn with a screw-like motion; to screw. [from 1806]
2. (figurative, by extension) To insinuate. [from 1813]
3. (transitive, intransitive) To untwist; to unravel, as the end of a thread or rope.
4. (obsolete, transitive, figurative, with at or up) To rub hard; to do a piece of work with passion.

Other uses

A nice looking cake shop in Japan: フィーゼ.

Building

Building

To clone the repository, do not forget to provide --recurse-submodules:

> git clone --recurse-submodules https://github.com/tokiwa-software/feeze

Documentation

NYI: Documentation mostly missing

Running and recording data

Currently, there is no main control window, but two command line tools that can be started as follows:

> make run 

will start the graphical interface that will display the last recorded data. If not data is found, this will wait until some data was recorded via

> make run_recorder

which will record scheduling data using sudo, so you will need sudo rights and enter your password. To see some fine-grain activity, this will start two threads that play high-frequence pthread_cond_signal/wait ping-pong.

Scheduling data will be passed to the graphical tool via shared memory mapped from file /tmp/feeze_events_recorder_data. To record new data, first delete this file using

> rm /tmp/feeze_events_recorder_data

Graphical Display

The displayed data

Threads are grouped by their processes.

Each thread is displayed as a horizontal line with the following properties

• thin grey for inactive threads in and aroudn the displayed area
• thin blue for ready or blocked threads
• think green for running threads
• thick dark green for threads that switch between running/ready/blocked at a time scale below the displayed resolution

Depending on the displayed area and time compression, inactive threads might get collapsed into thin lines.

Scrolling through the display

You have several options to scroll through the display:

• buttons 🠈🠊 / 🠊🠈 to compress or expand the time axis
• buttons +zoom / -zoom to zoom in or out (zoom both axes)

Mouse control

• left / middle mouse button to uncompress / expand the time axis, hold to auto-repeat
• shift and left / middke mouse to zoom in / out, hold to auto-repeat
• left mouse button and move to drag displayed area

Key control

• up/down/left/right arrow keys to move the displayed area