[gclist] Program behaviour

Hans Boehm boehm@hoh.mti.sgi.com
Mon, 14 Oct 1996 17:42:00 -0700


Marc Shapiro wrote:

"A more detailed analysis of cycles yields the following information:

 - Most cycles only contain objects allocated about the same time (allocated
   within ~150 allocations of each other); however Boehm's allocator breaks
   this locality by dispersing objects in memory (up to 500K bytes distance
   between objects in a cycle)."

This surprises me somewhat, given that free objects on a page should be
allocated to consecutive requests.  But distance is not a good measure of
locality.  How many pages are spanned by those cycles?

"There are a few other results that I can't really explain.  For instance every
program seems to tend change allocation behaviour at or near the magic number
of 2**20 bytes."

Is that just the GC interval?  It depends on heap size, so it's hard to tell
without more information.

Hans

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