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Date: Wed, 23 Oct 2013 08:43:12 +1100
Subject: Re: Python Front-end to GCC
From: Chris Angelico <rosuav@gmail.com>
To: python-list@python.org
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On Wed, Oct 23, 2013 at 4:27 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Tue, 22 Oct 2013 23:20:52 +1100, Chris Angelico wrote:
>
>> Considering that rapiding took about 1200ms (ish - again, cold cache)
>> previously, adding even just 250ms is noticeable.
>
> Please excuse my skepticism, but in my experience, that would probably
> mean in practice:
>
> ... rapiding took about 1200ms, plus or minus 200ms, plus 500ms if the
> system is under load, plus 800ms if the developer vagued out for a
> moment, plus 1900ms if he happened to be scratching an itch, plus 2700ms
> if the anti-virus happened to be scanning something, plus 4100ms if the
> dev decided this was a good time to take a sip of coffee, plus 437000ms
> if he needed to make the coffee first, plus 72000000ms if he was just
> taking a moment to check something on Reddit or answer an email...

Yes; and more importantly, at the times when it actually would be
used, the cache will likely be warm.

> You're right, of course, that 1/4 second is noticeable. I just find it
> hard to credit that it's *significant* in the circumstances you're
> describing. But I could be wrong.

Yeah, but the problem here is a fundamental of human nature. I
mentioned earlier that I was trying to "sell" the notion of an instant
pre-check of the code. I use one myself, have done for ages, and it's
helped me often enough that I don't care if it occasionally adds a
second to my time. (I have a few such assistants that involve
searching through recent git commit messages, so they can take
multiple seconds if the cache is cold. I don't care; once it's in
cache, it's way faster.) But imagine sitting beside a skeptical fellow
developer and saying, "Enable this line here and it'll catch these
sorts of bugs before you even spin it up in your testbox" - and he
hits F7 and notices that it takes twice as long as he's used to.
That's going to make it a pretty hard sell. That's why I wanted to get
the time cost of the smoke test as low as I possibly could, even on a
cold cache.

(I'm used to tough sells at my workplace. It took years before we
adopted source control.... yes, seriously. And even once we did, I had
to fight to get other developers to make useful commits and commit
messages. One in particular - who, fortunately, is no longer with us -
saw the whole thing as a nuisance that got in the way of his genius,
so he'd just commit once at the end of the day with a barely-useful
message. But then, he was pretty astounding in a lot of other areas,
too - really amazing... like using the For-Case paradigm in PHP with
an off-by-one error...)

ChrisA