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> [Average of 5 runs; this system only has 4GB so it consistently
> started to thrash during the Lua 5.2 runs.  Although Lua 5.2.0 and
> 5.2.1-work1 seem basically equivalent, and roughly similar to Lua
> 5.1.4 in terms of CPU usage, the 5.2 variants both used _twice_ as
> much memory as Luajit or Lua 5.1.4... (is the 5.2 GC really that
> different?)]

The difference may be just the default value for some GC parameters.
(That would also explain why 5.2 is faster; it may be running the GC
less agressively, and therefore trading memory for time.)

One characterisitc of these tests is that all of them seem to be
dominated by GC times. On one hand, that means they are not actually
focusing on the changes in 5.2.1. On the other hand, it may mean that
those changes have little impact on total program time. (As I said, most
programs that use long strings as indices produce these long strings
dynamically, and so the time to create and collect them makes indexing
time not relevant.)

-- Roberto