[plt-scheme] Random PLT Boehm pauses under Win2000/PLT203

From: Eric Kidd (eric.kidd at pobox.com)
Date: Mon Aug 25 16:59:28 EDT 2003

Hello!  Thanks for such a useful Scheme runtime.

I've been having some GC-related problems under Win2000 recently.  I'm
using PLT 203.  None of these problems are easily reproducible, but
Win2000 seems to be the common factor (we haven't tested much under
XP).  We're running PLT as a scripting environment inside a wxWindows
2.4-based C++ application.  Our application generates less garbage than
DrScheme, as far as we can tell.  For comparison purposes, application
performance on an 800MHz WinME box is perfectly fine.

Some of the following problems are probably the same problem.  I'm
listing them separately because the symptoms vary slightly.

* Problem #1: Big pauses on GC initialization and regular collection.

This happened for a while on one Win2K machine.  The pauses lasted
around 30 seconds.  Hitting Control-Alt-Delete and clicking on "Cancel"
would make the pause end immediately.  Re-installing the OS made this
problem go away.

* Problem #2: Indefinite pause on GC initialization.

This continues to happen on a newly-installed Win2K machine.  The user
in question claimed to wait several minutes without the application

* Problem #3: Occasional slightly-too-long GC pauses.

This happens on a number of Win2K machines.  GC tends to take several
seconds on a semi-regular basis.  We don't see this on other versions of

These erratic pauses are a potentially show-stopping problem on a major,
multi-person project.  We're not quite sure how to proceed from here,
and thought we'd ask on the list before switching to a different GC or
calling in a GC consultant.

If anybody has any suggestions, I'd be greatly in their debt.  Thank you
very much for any hints you can provide!


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