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Record and Replay Framework
C++ C Python CMake Assembly Shell Other
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rr is a lightweight tool for recording, replaying and debugging execution of applications (trees of processes and threads). Debugging extends gdb with very efficient reverse-execution, which in combination with standard gdb/x86 features like hardware data watchpoints, makes debugging much more fun. More information about the project, including instructions on how to install, run, and build rr, is at The best technical overview is currently the paper Engineering Record And Replay For Deployability: Extended Technical Report.

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System requirements

  • Linux kernel ≥ 3.11 is required (for PTRACE_SETSIGMASK).
  • rr currently requires an Intel CPU with Nehalem (2010) or later microarchitecture.
  • Running in a VM guest is supported, as long as the VM supports virtualization of hardware performance counters. (VMware and KVM are known to work; Xen does not.)
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