I continued working on the context stack stuff, then having got fed up with it, I decided (as a bit of relaxation and diversion) to look at whether perl's arithmetic operators could be easily optimised. The results are now smoking as smoke-me/davem/fast_arith2. This branch optimises +,-,* and ++/-- for the common cases, and makes the nbody benchmark (lots of floating-point vector arithmetic) about a third faster. 2015/10/19 0:36 process p5p mailbox 5:24 #124156: death during unwinding causes crash 2015/10/20 1:22 process p5p mailbox 0:48 #124156: death during unwinding causes crash 2:27 [perl #126309] 'x' operator on list causes segfault and confuses valgrind, 64-bit version 0:09 [perl #117341] av_undef's POD is confusing 2015/10/21 0:24 process p5p mailbox 4:58 #124156: death during unwinding causes crash 2015/10/22 7:00 make arithmetic faster 2015/10/24 3:00 make arithmetic faster 2015/10/25 3:00 make arithmetic faster SUMMARY: 11:10 #124156: death during unwinding causes crash 0:09 [perl #117341] av_undef's POD is confusing 2:27 [perl #126309] 'x' operator on list causes segfault and confuses valgrind, 64-bit version 13:00 make arithmetic faster 2:22 process p5p mailbox ------ 29:08 TOTAL (HH::MM) -- Never do today what you can put off till tomorrow.