Missing chart elements

[MatthewKhouzam]

Here is a list of core elements or information that are missing from certain chart types or views that make it difficult (or impossible) to use the results of the analysis. In some cases, this makes the view non-functional in practice. Related issues shown next to comment.

Chart type

Gantt Chart (Timeline chart)

ex. Resources Status, Thread Status

• Does bar colour mean something?
  • The state. If a color repeats it is probably the same state. We have a limited palette so color re-use occurs. (MatthewKhouzam)
• Does bar thickness mean something?
  • Width = duration
  • Height = either the state, there are height differences to help red-green colorblind users. IRQs are less high than userspace.
  • For frequency, higher = moar megahurts. (MatthewKhouzam)
• There is a large vertical offset between where the chart starts and where line labels start. So labels do not line up with the associated rows. (Row information is still available using the tooltip, but this isn't convenient) Time Graph: Align row labels with rows (recent Chrome only) #433

Resources Status

Description: "Show the state of CPUs (SYSCALL, RUNNING, IRQ, SOFT_IRQ or IDLE) and its IRQs/SOFT_IRQs as well as its frequency."

• How is the state of CPUs shown? The description "Show the state of CPUs (SYSCALL, RUNNING, IRQ," etc. implies that there would be chart elements labelled with those states
  • A given row is the an aspect of the state of the CPU. (MatthewKhouzam)
• This view also includes process/thread information?

Thread Status

Description: "Show the hierarchy of Linux threads and their status (RUNNING, SYSCALL, IRQ, IDLE)."

• How is thread status shown? "Show [...] their status (RUNNING, SYSCALL, IRQ, IDLE)" implies that there would be chart elements labelled with those states.

XY Chart

• Presumably not all XY Charts time-based. Is there an x-axis when the chart isn't time-based?
• No Y-axis: Can't know the unit or magnitude of the lines on the chart. XY Chart: Add y-axis #421
• No legend for lines (Only possible to know which is which by checking and un-checking the box) XY Chart: Identify chart lines (with labels or legend etc.) #434

CPU Usage

Description: "Show the CPU usage of a Linux kernel trace, returns the CPU usage per process and can be filtered by CPU core"

• What is the line that is shown by default? No checkboxes are checked.

Disk I/O View

Description: "Show the input and output throughput for each drive on a machine"

• Chart legend is not visible on a smaller resolution screen XY Chart: Identify chart lines (with labels or legend etc.) #434

Histogram

Description: "Show a histogram of number of events to time for a trace"

• Displays as an XY chart not a histogram. Is there a chart style missing? XY Chart: Support all styles in Trace Compass #45

Flame Chart

Description: "Show a call stack over time"

• Displays as empty for certain traces (ex. lttng-userspace-tracing). Is this because events are missing? Because the chart isn't implemented yet?

Originally posted by @ebugden in #296 (comment)

[MatthewKhouzam]

This should be a new issue, I think.

[MatthewKhouzam]

Resources Status

Description: "Show the state of CPUs (SYSCALL, RUNNING, IRQ, SOFT_IRQ or IDLE) and its IRQs/SOFT_IRQs as well as its frequency."

How is the state of CPUs shown? The description "Show the state of CPUs (SYSCALL, RUNNING, IRQ," etc. implies that there would be chart elements labelled with those states

A given row is the an aspect of the state of the CPU.

This view also includes process/thread information?
It is there. (color = process/thread)

I think the main issue is we have an alignment bug in chrome.

I will answer the rest in deferred time.

[MatthewKhouzam]

Does bar colour mean something?

The state. If a color repeats it is probably the same state. We have a limited palette so color re-use occurs.

Does bar width mean something?

Width = duration
Height = either the state, there are height differences to help red-green colorblind users. IRQs are less high than userspace.
For frequency, higher = moar megahurts.

[MatthewKhouzam]

I would note, most of the issues you bring up are solved with the legend that is not yet part of the theia front end.