Re: [PLUG] swappiness and ssd

You beat me to that Yixuan, my next question I was going to answer for myself was what exactly was the definition of "swappiness".

Rich Freeman, you and I both leave off for similar reasons. Did you know about this? Looks like a lower setting (like 0 LOL) might get swap to perform in a "sane" way.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Keith C. Perry, MS E.E.

Owner, DAO Technologies LLC

(O) +1.215.525.4165 x2033

(M) +1.215.432.5167

www.daotechnologies.com

From: "Guo Yixuan" <culu.gyx@gmail.com>
To: "Philadelphia Linux User's Group Discussion List" <plug@lists.phillylinux.org>
Sent: Friday, July 10, 2015 6:27:01 PM
Subject: Re: [PLUG] swappiness and ssd

Hi,

On Fri, Jul 10, 2015 at 6:16 PM, Keith C. Perry <kperry@daotechnologies.com> wrote:
>
> I know how to get usage but I didn't realize "swappiness" was a thing you could look up in proc. That's pretty cool...
>
> Even though, I leave swap off :D
>
> BTW, my swappiness still says 60- that's interesting. Maybe that's actually control point too? Can you do...
>
> echo 80 > cat /proc/sys/vm/swappiness
>
> ?

Documentation/sysctl/vm.txt is linux source tree explains swappiness:

715 ==============================================================

716

717 swappiness

718

719 This control is used to define how aggressive the kernel will swap

720 memory pages. Higher values will increase agressiveness, lower values

721 decrease the amount of swap. A value of 0 instructs the kernel not to

722 initiate swap until the amount of free and file-backed pages is less

723 than the high water mark in a zone.

724

725 The default value is 60.

726

727 ==============================================================

It's easy to find docs on other parameters just by grepping.

Yixuan

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