How do I measure time between two markers in gtkwave?

Question

I am simulating my verilog design using iverilog and dump the output to an fst file. I am then using gtkwave to view the waveform. gtkwave allows me to add a number of markers. How do I then measure the delta between any two markers. I read through the gtkwave manual, and it talks about the Toggle Delta-Frequency option as

Toggle Delta-Frequency

allows you to switch between the delta time and frequency display in the upper right corner of the main window when measuring distances between markers. Default behavior is that the delta time is displayed.

However I do not see any delta value being displayed in my waveform window.

Am I missing some option here?

I am on Windows running gtkwave under cygwin.

Answer 1

It's not for the named markers, but is for the primary vs baseline one. Measure using the red (left mousebutton) marker vs the white one (middle). Clicking the middle mouse button toggles the white marker on and off. You'll see the Marker: time change from a numeric value to something like B+/- a value.

-Tony