An indicator for long-running cells?

[krassowski]

Sometimes I want to narrow down which cells took long to execute. Scrolling the notebook to read time diffs in footers of cells is time consuming. I would love to have an opt-in visual indicator to aid such search, or another way to list cells that took longest to execute in any given notebook. Some ideas include:

1. a bar next to the cell with fill depending on the execution time, possibly using log scale (e.g. 90th percentile = red, 75th percentile yellow, 50th percentile and below = white)
2. same as above but as a thick (2-3px) border/outline of the cells
3. a clock icon shown next to cells with execution time > 75th percentile
4. a command opening a popup with list of 5 cells with longest execution time (where clicking takes you to the cell)
5. same as above but in a sidebar

Whether to use percentiles or absolute cutoffs could be customisable in settings.

Would anyone else find this helpful? Are any of those in scope for this extension?

[mlucool]

This sounds in scope.

The visual ideas (1-3) seem like we could use a quick mockup/some refinement before going forward. Maybe a heatmap dot that changes color relative to the time (and log or linear scale can be options).

Between 4 and 5, I'd lean towards 4. If you have a popup, it seems like there is no need to limit it to 5 cells, might as well list all cells? These are maybe a little less in scope, but I don't mind them here given the general name of what this extension does.