Align a variable on the stack.
Marc Schütz via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Fri Nov 6 03:38:28 PST 2015
On Friday, 6 November 2015 at 11:37:22 UTC, Marc Schütz wrote:
> Ok, benchA and benchB have the same assembler code generated.
> However, I _can_ reproduce the slowdown albeit on average only
> 20%-40%, not a factor of 10.
Forgot to add that this is on Linux x86_64, so that probably
explains the difference.
>
> It turns out that it's always the first tested function that's
> slower. You can test this by switching benchA and benchB in the
> call to benchmark(). I suspect the reason is that the OS is
> paging in the code the first time, and we're actually seeing
> the cost of the page fault. If you a second round of benchmarks
> after the first one, that one shows more or less the same
> performance for both functions.
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