IME it's not only slow, but also very memory-hungry. As a result it's hard to use it to debug heisenbugs, because you have to have a decent idea of where the bug is, so you can start recording at that point. But of course if you know even roughly where the bug was, debugging isn't nearly as hard...
VMWare had record-and-replay debugging functionality which was functionally similar to gdb's backwards debugging, although its implementation was a lot different, which allowed it to scale to recording much longer threads of execution. We used this at Mozilla to find a number of super-tricky bugs; it was pretty awesome. Unfortunately this feature was nixed in vmware workstation 8 [1].
Comments
IME it's not only slow, but also very memory-hungry. As a result it's hard to use it to debug heisenbugs, because you have to have a decent idea of where the bug is, so you can start recording at that point. But of course if you know even roughly where the bug was, debugging isn't nearly as hard...
VMWare had record-and-replay debugging functionality which was functionally similar to gdb's backwards debugging, although its implementation was a lot different, which allowed it to scale to recording much longer threads of execution. We used this at Mozilla to find a number of super-tricky bugs; it was pretty awesome. Unfortunately this feature was nixed in vmware workstation 8 [1].
[1] http://www.replaydebugging.com/
That's very interesting! Why did they remove that feature if it was so awesome?
We still have it working on a box in the office here. I used it last week ;-)