On 2 December 2014 at 19:15, Mark S. Miller <erig...@google.com> wrote: >> In both minor or major collection both m and v are immediately >> reclaimed, because neither is strongly reachable at that point > > which shows the asymmetry, and that v8 is effectively optimizing for > the wrong side of that asymmetry. By adopting what Allen and I refer > to as the transposed representation (as opposed to your transposed > representation), you'd instead be able to say of the common scenario > >> In both minor or major collection both k and v are immediately >> reclaimed, because neither is strongly reachable at that point > > which would be much more valuable than any other efficiency issue > discussed in this thread.
What I'm saying is that this is a theoretical conclusion at which you arrive only under various simplifying and idealistic assumptions (such as life time being the only factor that matters). I maintain that there is no evidence yet that this actually translates to better overall performance in practice, and I have severe doubts that it would. I don’t want to reiterate the concerns that I already raised in an earlier thread, but the executive summary is: Good performance absolutely wants an object layout that is stable and compact. The transposed weak map implementation pretty much is an antithesis to that. It hence induces a potential cost on all key objects (and all their uses throughout a program) instead of just the maps. That is a case of optimising for the wrong thing as well. (Back to the actual topic of this thread, you still owe me a reply regarding why .clear is bad for security. ;) ) /Andreas _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
