On Wed, Nov 16, 2005 at 08:32:01PM +0100, Leopold Toetsch wrote: : >Some basic questions: is there a notion of "current time" in Parrot, : >like : >a cycle counter or anything? I don't see any instructions I could get : >one : >from inside a PASM program, and I didn't see any of the .c files : >keeping : >track of one... : : No there is nothing like a timestamp / cycle counter.
Conceptually, being able to virtualize time may be THE crucial concept of STM. Otherwise it just degenerates to ordinary locking. But with virtual time you can often optimize things to not block merely by pretending things happened in a different order, when that order doesn't matter. STM lets you take advantage of the holes in partial ordering without imposing complete ordering. At least, that's my take on it, but I'm no expert. I'm just the resident philosopher--and unfortunately being a "friend of sophos" is no guarantee of being right... Larry
