3 ms·

I suggest you give it try, it's quite remarkable (disclaimer : I'm a pernosco customer) . You need to adjust your mindset to the way it works (I haven't seen an

I suggest you give it try, it's quite remarkable (disclaimer : I'm a pernosco customer) . You need to adjust your mindset to the way it works (I haven't seen any similar tool elsewhere, so to me it looks very different from a traditional forward debugger), but it's well worth spending a little bit of time with it. In particular, because it shows the whole 'dataflow history' (how a specific value flows through your program), it makes learning an unknown codebase (or a codebase you think you know for that matter...) much easier. Other features such as 'show me all calls to function f along with their parameters' help provide similar insights. I don't like debuggers, and used to delay as much as possible reaching for gdb and its cousins, but with pernosco, it's pretty much the opposite : I know that I will find my (potentially nasty) bug within a few minutes, by focusing on the 'big picture' provided by pernosco instead of wasting time working around the limitations of a regular debugger.

nyanpasu64 5y ago
I tried uploading a trace... which promptly failed due to Qt running RDRAND and Pernosco detecting a desync on playback. I do think it's a cool idea (assuming the binaries are symboled and everything). However in my recent debugging, I've noticed that sometimes I recompile and run programs to change what logging I add, or rerun programs because I screwed up my breakpoints (pernosco could fix), but sometimes I recompile to change the code behavior and observe how the visible output of an app changes (which probably can't be simulated in a trace in general, aside from identifying what downstream code would be affected by changing a variable). So this won't be a complete solution for debugging, especially given that uploading more teaces costs extra money, but I assume it will be a powerful tool to have.
- khuey 5y ago
  Yeah we had to hack around this Qt bug https://bugreports.qt.io/browse/QTBUG-91071 https://bugreports.qt.io/browse/QTBUG-91071 but it's fixed now.

nyanpasu64 5y ago

I tried uploading a trace... which promptly failed due to Qt running RDRAND and Pernosco detecting a desync on playback. I do think it's a cool idea (assuming the binaries are symboled and everything). However in my recent debugging, I've noticed that sometimes I recompile and run programs to change what logging I add, or rerun programs because I screwed up my breakpoints (pernosco could fix), but sometimes I recompile to change the code behavior and observe how the visible output of an app changes (which probably can't be simulated in a trace in general, aside from identifying what downstream code would be affected by changing a variable). So this won't be a complete solution for debugging, especially given that uploading more teaces costs extra money, but I assume it will be a powerful tool to have.

khuey 5y ago
Yeah we had to hack around this Qt bug https://bugreports.qt.io/browse/QTBUG-91071 https://bugreports.qt.io/browse/QTBUG-91071 but it's fixed now.