Flush the Backend buffer
#691
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…g all the `Event`s so that we never miss any.
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aneksteind
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Sep 27, 2022
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I believe this (and #683) have finally fixed #613. I haven't noticed anymore flaky CI failures since. @aneksteind, have you noticed any? If not, I'll finally close that issue. |
This was referenced Oct 10, 2022
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Fixes #687. This adds a single (main) thread instrumentation runtime in addition to the existing background thread runtime. The single-threaded, main thread runtime greatly simplifies the logic, helping to easily and quickly expose bugs, like #613, which I solved in #691 as soon as I added the single-threaded runtime. This, I think, is the main motivation for adding this, though it may also be faster in certain cases, and would allow instrumented code to run in single-threaded environments in the future. The runtime, like the backend, is dynamically selected through `$INSTRUMENT_RUNTIME`, which must be either `fg` for the main thread runtime, or `bg` for the background thread runtime. This is exactly how `$INSTRUMENT_BACKEND` currently works for the backend.
This was referenced Oct 16, 2022
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Fixes #689.
Normally the
BufWriterinLogBackendisflushed indrop, but since all of this runs from a static or a background thread, no destructors are run (reliably at least; not sure about the background thread case). Thus, we need to explicitlyflushthe buffer. I believe this may be the remaining cause of #613.This fix adds a
flushmethod totrait WriteEvent, which is called after allEvents have been written so that we never lose any of theEvents. It's implemented by delegating toWrite::flush, both forBufWriterinLogBackendandstderr()inDebugBackend(though that one is usually unbuffered).I discovered this while implementing #687, as the missing
flushis reliably detected when running theBackendon the main thread.