[gclist] What to say about GC.

[Hans Boehm]

For collectors that have to track modified objects/pages, it seems to be useful
to optionally check this information by checksumming whenever possible.  That's
especially important if rarely excercised system calls are involved.  My
experience has been that such errors are harder to isolate than most.  A long
time ago I managed to invert all the dirty bits for our collector.  Tests still
ran for a while ...

Most of the other hard-to-trace bugs for our collector involved
concurrency/synchronization issues.  I've occasionally resorted to maintaining
a history buffer to remember interesting events without drastically affecting
timing.

Hans

-- 
Hans-Juergen Boehm
boehm@mti.sgi.com