Re: Mutable arrays
Re: Mutable arrays
- Subject: Re: Mutable arrays
- From: email@hidden
- Date: Mon, 20 Oct 2008 15:40:35 +0100
Michael Ash wrote on 20/10/2008 15:31:01:
> On Mon, Oct 20, 2008 at 1:35 AM, j o a r <email@hidden> wrote:
> > Some general suggestions for best practices wrt. optimizations:
> >
> > 1) Measure first
> > 2) Implement supposed optimization
> > 3) Measure to see the impact of the code change
> > 4) Based on the result of #3, either scrap your changes,
or
> > document the optimized code
>
> And don't forget step 0:
>
> 0) Don't even bother
>
> A lot of people optimize code that's already plenty fast. A lot of
> people optimize code that *hasn't even been written yet*. This is
> foolish. Write your code to be easy to understand and as bug-free as
> you can get it. And then, only if it's not running as fast as you need
> it to, should you even start to consider the possibility of thinking
> about beginning to investigate optimizing the code.
I think that's only frequently, not usually or always, the approach to
take. For instance if you have a specific performance requirement, and
when you prototype the proposed solution you find the performance to be
way off the requirement, it's best to go back to the boxes on the paper.
Even Instruments is unlikely to help you get your slow design orders of
magnitude faster, nor your bloated design orders of magnitude more svelt.
I've been involved on a project like that in a previous job, where we had
a requirement to process thousands of things/sec and our existing solution
was capable of tens/sec. Rather than see what we could eke out of our
solution, we went back to the whiteboard and optimised the design. In that
case, this was not a foolish thing to do.
Cheers,
Graham.
--
Graham Lee
Senior Macintosh Software Engineer, Sophos
Tel: 01235 540266 (Direct)
Web: http://www.sophos.com
Sophos - Security and Control
Sophos Plc, The Pentagon, Abingdon Science Park, Abingdon,
OX14 3YP, United Kingdom.
Company Reg No 2096520. VAT Reg No GB 348 3873 20.
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