Include original process name in worker thread name (#14153)

Authored by enolan on Sep 20 2017, 5:22 PM.



Prior to this commit, worker OS thread were renamed to "ghc_worker" when
spawned. This was annoying when reading debugging messages that print the
process name because it doesn't tell you *which* Haskell program is generating
the message.

This commit changes it to "original_process_name:w", truncating the original
name to fit in the kernel buffer if neccesary.

Test Plan


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rGHC Glasgow Haskell Compiler
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enolan created this revision.Sep 20 2017, 5:22 PM
enolan updated this revision to Diff 14016.Sep 20 2017, 5:52 PM

Fix some OS specific #ifdef stuff.

bgamari added inline comments.Sep 20 2017, 7:59 PM

It looks like this isn't going to work on Windows; you'll need to guard this on linux_HOST_OS.


Is there no way we can do something sensible on Windows?

enolan updated this revision to Diff 14017.Sep 20 2017, 8:22 PM

Fix platform specific issue: use VLA over alloca()

bgamari edited edge metadata.Sep 20 2017, 10:30 PM

Indeed, this looks reasonable to me. Let's see what Harbormaster says.

Phyx added a subscriber: Phyx.Sep 21 2017, 3:00 AM
Phyx added inline comments.

Yes GetModuleFileName passing a Null for the module gets you the entry point name

enolan added inline comments.Sep 21 2017, 11:48 AM

On Windows, the threads aren't renamed, so there's nothing to do. If you look in createOSThread in rts/win32/OSThreads.c you can see the name parameter is unused.

Phyx added a comment.Sep 21 2017, 11:58 AM

You can use SetThreadDescription which was introduced in Windows 10. But
anyway it doesn't work now so there's no regression

bgamari accepted this revision.Sep 22 2017, 12:03 PM

Looks good to me. Thanks @enolan!

This revision is now accepted and ready to land.Sep 22 2017, 12:03 PM

How long do the Windows CI builds usually take? It's almost 48 hours old and AFAICT hasn't started yet.

This revision was automatically updated to reflect the committed changes.