Some generic STM bits of wisdom: - STMs in "standard" languages (e.g. C, C++) suffer from having to track all memory references. THis overhead means the STM code typically starts 3x to 10x slower than non-STM code, which is a pretty stiff penalty to recover from. If you're only getting a 3x speedup on your 4-core machine, but you're starting 3x down then you're not ahead. - Abort/retry rates can commonly exceed 90% (e.g. 1-in-10 attempts succeeds) - There are very few languages w/real TM support, so "good" TM writing styles are still being figured out - THere are very few TM implementations, so "good" STM implementations are still being figured out - even the "good" feature set isn't really well known.
- Clojure dodges several of these bullets (no need to track everything; already paying a high abstraction penalty (commonly), so the STM slowdown isn't really interestingly large (e.g. it's 3x over some base speed, not 3x on top of Clojure) - I DO have a Clojure program where the retry/fail rate approaches 99.99% - There are NOT good tools to figure out why TM's fail - if you have a high fail rate it's often hard to figure out even that! Cliff --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
