BPF: hotspot: add limited heuristic for x86-64 epilogue #138
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Add a simple heuristic for x86-64 epilogue checking that should be able to not produce too many false positives and yet catch the most probable asynchronous stop points where the CPU perf might fire. Also ensure that epilogue parsing is attempted only on the top frames to further reduce likelyness of false positives and reduce ebpf code size. fixes open-telemetry#136
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The maximum distance from 'popq %rbp' to 'retq' seems to be 12 bytes, and we need at least one byte before rip. Report the used epilogue method in debug messages
athre0z
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Aug 30, 2024
…ry#138) Add a simple heuristic for x86-64 epilogue checking that should be able to not produce too many false positives and yet catch the most probable asynchronous stop points where the CPU perf might fire. Also ensure that epilogue parsing is attempted only on the top frames to further reduce likelyness of false positives and reduce ebpf code size. fixes open-telemetry#136
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Add a simple heuristic for x86-64 epilogue checking that should be able to not produce too many false positives and yet catch the most probable asynchronous stop points where the CPU perf might fire.
Also ensure that epilogue parsing is attempted only on the top frames to further reduce likelyness of false positives and reduce ebpf code size.
fixes #136