new DragonFly-3.2 scheduler and PostgreSQL comparision with FreeBSD 9.1-RC1
Andriy Gapon
avg at FreeBSD.org
Sun Oct 14 09:47:25 UTC 2012
on 14/10/2012 00:27 Pedro Giffuni said the following:
> Actually ...
>
> On 10/13/2012 13:38, Jakub Lach wrote:
>> I'm not at all up to date with DragonFly, so does anybody know
>> what did they change so spectacularly between 3.0/3.2?
>>
> Their explanation of the changes is here:
>
> http://www.shiningsilence.com/dbsdlog/2012/09/19/10403.html
>From the article:
(3) It will detect process block/wakeup events which e.g. tie two
processes together, and will try to move the process pairs closer
to each other using that information.
For example, if you have many postgres clients and servers on a
large server, enough to load down all cores, the client and
server pairs will be localized to the same socket, thus making
use of chip caches to facilitate communications between the two
processes.
This sounds like a nice heuristic. Currently our code unintentionally does the
opposite quite often.
--
Andriy Gapon
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