| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Scott Carey <scott(at)richrelevance(dot)com> |
| Cc: | Greg Smith <greg(at)2ndquadrant(dot)com>, Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, "david(at)lang(dot)hm" <david(at)lang(dot)hm>, Steve Clark <sclark(at)netwolves(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Linux: more cores = less concurrency. |
| Date: | 2011-04-15 06:57:45 |
| Message-ID: | BANLkTi=Qv8mOzD_PbdWcHwNkZcMX-PbwFw@mail.gmail.com |
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| Lists: | pgsql-performance |
On Fri, Apr 15, 2011 at 12:42 AM, Scott Carey <scott(at)richrelevance(dot)com> wrote:
> I do know that dual-pivot quicksort provably causes fewer swaps (but the
> same # of compares) as the usual single-pivot quicksort. And swaps are a
> lot slower than you would expect due to the effects on processor caches.
> Therefore it might help with multiprocessor scalability by reducing
> memory/cache pressure.
I agree, and it's quite non-disruptive - ie, a drop-in replacement for
quicksort, whereas mergesort or timsort both require bigger changes
and heavier profiling.
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