Front page | perl.perl5.porters |
Postings from September 2009
Re: dual pivot quicksort
Thread Previous
|
Thread Next
From:
Abigail
Date:
September 28, 2009 04:59
Subject:
Re: dual pivot quicksort
Message ID:
20090928115919.GD5424@almanda
On Fri, Sep 25, 2009 at 03:58:27PM +0100, Nicholas Clark quoted John P. Linderman:
>
> With modern architectures, locality and pipelining
> can matter a bunch on real performance. Somebody
> in 2) observed that comparison is read-only, so it
> doesn't invalidate caches. But it can break pipelining.
> And, if you are comparing *and* swapping native integers,
> you get huge locality wins, because everything you need
> is in the partition you are sorting. If you are sorting
> pointers to things, not things, you don't get that huge
> locality win.
In Perl, comparison isn't always read-only. Even in the absense of ties
and overloads, there's always the string <-> number conversion that may
cause writes.
Abigail
Thread Previous
|
Thread Next