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Re: How to Generate a Long String of the Same Character

From: Neil R. Ormos
Subject: Re: How to Generate a Long String of the Same Character
Date: Mon, 19 Jul 2021 01:46:40 -0500 (CDT)

Bob Proulx wrote:

> That's looking pretty good.  Let's compare it against the reference
> above so one can see how slow my machine is about such things.
>     $ time awk 'BEGIN{sizelim=100000000; a="x"; while (length(a) < sizelim) 
> {a=a a}; a=substr(a, 1, sizelim); print length(a);}'                          
>     100000000
>     real    0m1.469s
>     user    0m0.815s
>     sys     0m0.654s
> I am running this on an older Intel Core i5 CPU 750 2.67GHz.

That seems really odd.  It takes under 0.5 seconds
of elapsed time on a machine with a 25-watt mobile
Core 2 Duo CPU that maxes out at 2.26 GHz.

I tried your dd | tr | gawk solution and found the
times vary bizarrely on machines where the pure
gawk solution has run-times roughly in-line with
what I'd expect.  Even the elapsed times of
consecutive individual runs of the dd | tr | gawk
solution vary strangely.

Also, I think the blocksize parameter should be
bs=1MB to get blocks of 10^6 bytes and not 2^20

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