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From: "G. Branden Robinson" <g.branden.robinson@gmail.com>
Newsgroups: gnu.bash.bug
Subject: Re: Should [[ -v 1 ]] be supported?
Date: Thu, 27 Dec 2018 20:57:12 -0500
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At 2018-12-27T19:47:08-0600, Peng Yu wrote:
> On Thu, Dec 27, 2018 at 7:37 PM G. Branden Robinson
> > As others have noted, if you are worried about marginal performance
> > impacts this small, margin you are probably writing in the wrong
> > language, or distracting yourself with tiny details when you do not even
> > know the cyclomatic complexity of your code or the big-O classification
> > of your algorithms.
> >
> > Attack those problems first, and see what you discover.
>=20
> The problem is that bash is not systematically profiled for
> performance at all. I am doing it step it by step.

You're whacking moles.  Use a profiler.  That's what they're for.

https://www.thegeekstuff.com/2012/08/gprof-tutorial/

> There are many more that I have already tested. You can not dismiss
> this one just because it may not have a large impact.

Yes, I can.  You need to identify where bash is _actually_ spending most
of its execution time, and a profiler can help you do that.

You also need to establish acceptance criteria.  All but the most
finely-tuned code can be made more performant; often raw performance
comes at a cost, such as the abandonment of memory safety.  Aliasing
problems are one example in software, and the Spectre and Meltdown
suites of cache-related timing attacks are an examples from hardware.

What is it you're trying to achieve?  State your goal in terms that are
"SMART":

(S)pecific
(M)easurable
(A)ttainable
(R)easonable
(T)imely

Just the first four would be a good start.

Regards,
Branden

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