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From: "me at serhei dot io" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug bpf/25218] stapbpf loses perf_events when writing to interactive terminal
Date: Fri, 22 Nov 2019 23:46:00 -0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D25218

Serhei Makarov <me at serhei dot io> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |me at serhei dot io
            Summary|stapbpf losing perf_events  |stapbpf loses perf_events
                   |                            |when writing to interactive
                   |                            |terminal

--- Comment #1 from Serhei Makarov <me at serhei dot io> ---
My suspicion is that the perf_events buffer used to receive transport messa=
ges
fills up while the stapbpf process is delayed writing output. This results =
in
transport messages being overwritten and the 'lost perf_events' warning bei=
ng
generated.

When stapbpf output is redirected to a file, there is no I/O delay, and
perf_events are consumed before the buffer overflows.

If my suspicion is true, this could be solved by receiving transport messag=
es
in a separate thread.

--=20
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