1279597 - Add 'notelemetry.obj' to VS2015 link stage

Status: RESOLVED WONTFIX

(Firefox Build System :: General, defect)

Description

[Adam Roach [:abr]]

According to <https://www.infoq.com/news/2016/06/visual-cpp-telemetry>, VS2015 update 2 (which I believe we're using on m-c) inserts calls into MS's telemetry system. While probably harmless, this is unnecessary and smells fishy. The behavior can be suppressed by adding 'notelemetry.obj' to the link lines.

We should probably do that.

Comment 1

[Gregory Szorc [:gps]]

The source thread at https://www.reddit.com/r/cpp/comments/4ibauu/visual_studio_adding_telemetry_function_calls_to/ has many more details, including a post from a Microsoft engineer saying this will be removed in vs2015u3.

Comment 2

[Gregory Szorc [:gps]]

I think the Internet is over-reacting. According to https://habrahabr.ru/post/281374/, this "telemetry" appears to just be ETW events indicating when a CRT-using application starts and stops (pay attention to the XML in the post).

Nearly everything in Windows emits ETW events. (ETW is the main tracing framework in Windows.) Spawning processes and threads emit ETW events.

ETW events don't automatically get sent to Microsoft. They *can*, but that's because ETW is a generic tracing and recording framework - not spyware. An analogy would be that these ETW events are output from `strace`. You can upload the output from `strace` but you likely don't unless you are reporting a problem or something.

Assuming there aren't more ETW events - specifically ETW events that could cause performance problems (and you'd need them in tight loops because ETW is pretty light weight - I wouldn't be too concerned about this. This appears benign and probably isn't worth our time to work around it.

Again, I think the Internet is over-reacting and inventing a privacy or performance concern where there is none. Again, this assumes the "telemetry" events are limited to crt start and stop, which is all I can find evidence of.

Comment 3

[Gregory Szorc [:gps]]

The Internet over-reacted. Not worth our effort to change anything.