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From: "Cédric Villemain" <cedric@2ndquadrant.com>
To: linux-mm@kvack.org
Cc: Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: mincore() & fincore()
Date: Thu, 25 Jul 2013 17:07:10 +0200	[thread overview]
Message-ID: <201307251707.11159.cedric@2ndquadrant.com> (raw)
In-Reply-To: <201307251658.33548.cedric@2ndquadrant.com>

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[sorry, previous mail was sent earlier than expected]

> First, the proposed changes in this email are to be used at least for 
> PostgreSQL extensions, maybe for core.
> 
> Purpose is to offer better monitoring/tracking of the hot/cold areas (and 
> read/write paterns) in the tables and indexes, in PostgreSQL those are by default 
> written in segments of 1GB.
> 
> There are some possible usecase already:
> 
>  * planning of hardware upgrade
>  * easier configuration setup (both PostgreSQL and linux)
>  * provide more informations to the planner/executor of PostgreSQL
> 
> My ideas so far are to 
> 
>  * improve mincore() in linux and add it information like in freeBSD (at 
>    least adding 'mincore_modified' to track clean vs dirty pages).
>  * adding fincore() to make the information easier to grab from PostgreSQL (no 
>    mmap)
>  * maybe some access to those stats in /proc/
> 
> It makes years that libprefetch, mincore() and fincore() are discussed on linux 
> mailling lists. And they got a good feedback... So I hope it is ok to keep on 
> those and provide updated patches.

Johannes, I add you in CC because you're the last one who proposed something. 
Can I update your patch with previous suggestions from reviewers ?

I'm also asking for feedback in this area, others ideas are very welcome.

-- 
Cédric Villemain +33 (0)6 20 30 22 52
http://2ndQuadrant.fr/
PostgreSQL: Support 24x7 - Développement, Expertise et Formation

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  reply	other threads:[~2013-07-25 15:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-25 14:58 Cédric Villemain
2013-07-25 15:07 ` Cédric Villemain [this message]
2013-07-25 15:32   ` Johannes Weiner
2013-07-26  1:55     ` Wanpeng Li
2013-07-27 20:08       ` Cédric Villemain
2013-07-26  1:55     ` Wanpeng Li

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