Hello, Mark H Weaver <m...@netris.org> skribis:
> Here's one specific data structure idea: we have a "vlist" data > structure, currently written in Scheme, but in my opinion it would be > useful to rewrite it in C for better efficiency. FWIW, I’m not convinced that this is a fruitful approach. First, because Guile 2.0 has allowed us to write more things in Scheme, and I’d like to keep it this way. ;-) Second, because a very important optimizations would rather be to fiddle with the GC so that vlists, which are base + offset pairs, would not have to be heap-allocated, as vlist.scm says: ;; XXX: Allocating a <vlist> record in addition to the block at each ;; `vlist-cons' call is inefficient. However, Bagwell's hack to avoid it ;; (Section 2.2) would require GC_ALL_INTERIOR_POINTERS, which would be a ;; performance hit for everyone. I remember Andy did some measurements showing that ‘vhash-assoc’ was often high in the profile when running the compiler. One thing that could be done is to run a C-level profiler to see exactly what’s going on, and which optimizations could help. WDYT? Thanks, Ludo’.
