[PROF-4081] Make threads with empty backtrace visible #1719
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As documented in the code, there's a few situations in which a thread can have an empty backtrace. Previously, these threads were not visible in the profiling UX, which was a gap in our provided information. (It also could be confusing, for instance, if a thread spent some time executing Ruby and some time in native code, as happens with the Iodine web server, the "wall clock time" would not add up to 60s in a regular profile, because we ignored these threads). To fix this, we now replace empty backtraces with a fake stack that displays `(In native code)`. We currently have no way of showing what's up in native code (is the code running? is the thread idle? we don't know), but at least we know it's there.
marcotc
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Oct 15, 2021
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…K_IN_NATIVE_CODE` This feature was already supported by the `Datadog::Profiling::Collectors::OldStack` in much the same manner (it's called `SYNTHETIC_STACK_IN_NATIVE_CODE` there, but I think placeholder is a better name). See #1719 for details. I have validated that the detection in `rb_profile_frames` correctly works for the ffi and iodine gems as well.
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…K_IN_NATIVE_CODE` This feature was already supported by the `Datadog::Profiling::Collectors::OldStack` in much the same manner (it's called `SYNTHETIC_STACK_IN_NATIVE_CODE` there, but I think placeholder is a better name). See #1719 for details. I have validated that the detection in `rb_profile_frames` correctly works for the ffi and iodine gems as well.
ivoanjo
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May 20, 2022
…K_IN_NATIVE_CODE` This feature was already supported by the `Datadog::Profiling::Collectors::OldStack` in much the same manner (it's called `SYNTHETIC_STACK_IN_NATIVE_CODE` there, but I think placeholder is a better name). See #1719 for details. I have validated that the detection in `rb_profile_frames` correctly works for the ffi and iodine gems as well.
ivoanjo
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May 23, 2022
…K_IN_NATIVE_CODE` This feature was already supported by the `Datadog::Profiling::Collectors::OldStack` in much the same manner (it's called `SYNTHETIC_STACK_IN_NATIVE_CODE` there, but I think placeholder is a better name). See #1719 for details. I have validated that the detection in `rb_profile_frames` correctly works for the ffi and iodine gems as well.
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As documented in the code, there's a few situations in which a thread can have an empty backtrace. Previously, these threads were not visible in the profiling UX, which was a gap in our provided information.
(It also could be confusing, for instance, if a thread spent some time executing Ruby and some time in native code, as happens with the Iodine web server, the "wall clock time" would not add up to 60s in a regular profile, because we ignored these threads).
To fix this, we now replace empty backtraces with a fake stack that displays
(In native code). We currently have no way of showing what's up in native code (is the code running? is the thread idle? we don't know), but at least we know it's there.