Re: Quality-of-Life patches

[Viacheslav Usov <via.usov@...>]

On Fri, Feb 25, 2022 at 8:09 PM Sean Conner <sean@conman.org> wrote:

> > When you have
> > preload-costly embedded libraries, or just really many embedded
> > libraries and many Lua VMs in your application, you have to consider
> > the cost of preloading, it may have a noticeable effect on
> > performance.
>
>   Having done this for work (well, not embedding luasocket, but I have a
> custom build of Lua with 81 modules built in, 34 of which are in C, and 47
> in Lua), I haven't noticed any appreciable different in speed from running
> the normal Lua interpreter.

Performance is not just speed, it is also storage.

> Lua modules in Lua have to be "compiled" in
> either case.

This remark makes me wonder what your baseline really was.

Certainly the cost of compiling 47 Lua modules vs not compiling them
at all should be measurable. Then, of course, this cost should be
viewed in the perspective of what else your Lua states are doing.

I was thinking about a situation when a Lua state (VM) may end up
using only a small number of preloaded modules, and when its "main"
payload might be relatively light and short-lived. If all your Lua
states always use all of the preloaded libs, or stay on doing some
heavy lifting, then, sure, the act of preloading has a negligible
run-time cost.

Cheers,
V.