Re: Fun with table rehash
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- Subject: Re: Fun with table rehash
- From: Paul Ducklin <pducklin@...>
- Date: Fri, 2 Oct 2020 14:16:49 +0000
Lua 5.4.1 on slackware-current (64-bit libraries only, Linux kernel 5.4.69) with 16GB RAM, nothing else of significance going on.
With the non-integer key ‘slow’ in the table:
77.9 seconds
Without it:
33.8 seconds
That ratio of about 2.3-to-1 (78/34) shows up repeatedly.
(I upped the loop to “j=1,1e9” otherwise it ran too quickly to give useful measurements, though at “j=1.1e8” I got similar results with 7.6sec and 3.3 sec.)
> On 30 Sep 2020, at 14:14, Egor Skriptunoff <egor.skriptunoff@gmail.com> wrote:
>
> Hi!
>
> This program runs very fast:
>
> local t = {}
> -- t.slow = true
> for j = 1, 1e6 do t[j], t[-j] = 0, nil end
>
> But if you uncomment the line with the "slow" option...
>