To swap or not to swap ;-) (was RE: To lvm or not to lvm)

[Michael Butash]

So interestingly enough I was looking at my swap from this convo, and
surprisingly noticed that I'd never added any swap to this system!  I built
the swap lvm slice, but never added it to the fstab, don't remember if
on-purpose or not.  This system has 128gb of ram, so not that I notice
really, but might explain why I might see some weird lagging at times.  I
usually blame (crap) compositing...

I suppose I've been using this pc for a couple years now without swap, so
it *is* doable (with a lot of ram), but I think I might enable it and see
if things are any better with than without swap.

-mb

On Mon, Sep 24, 2018 at 9:46 AM Stephen Partington <cryptworks at gmail.com>
wrote:

> YEah, So I always consider installing at least a GB or two for swap and
> setting swappiness to 0 for that. It also might explain why Mr Butash still
> can see a difference in performance on what he does when swap is there or
> not.
>
> On Mon, Sep 24, 2018 at 9:44 AM Carruth, Rusty <Rusty.Carruth at smartm.com>
> wrote:
>
>> Wow, that quote is very interesting.
>>
>>
>>
>> Thanks!
>>
>>
>>
>> (google found the reference for me.  One of them (possibly the original
>> reference others are using) is
>> https://www.kernel.org/doc/gorman/html/understand/understand014.html )
>>
>>
>>
>> I read it, and it appears that the reference is talking primarily about
>> what the kernel does.  I kept searching and couldn’t find any definitive
>> statement that a PROGRAM could request this, however apparently some JVM
>> somewhere can do something with memory that almost requires there be swap
>> to keep the JVM from getting killed by the OOM monster…  er, killer… er,
>> task.. er, whatever.
>>
>>
>>
>>
>>
>> Rusty
>>
>>
>>
>> *From:* PLUG-discuss [mailto:plug-discuss-bounces at lists.phxlinux.org] *On
>> Behalf Of *Stephen Partington
>> *Sent:* Sunday, September 23, 2018 12:18 AM
>> *To:* Main PLUG discussion list
>> *Subject:* Re: To swap or not to swap ;-) (was RE: To lvm or not to lvm)
>>
>>
>>
>> I have found some applications use swap with direct calls.
>>
>>
>>
>> "A significant number of the pages referenced by a process early in its
>> life may only be used for initialisation and then never used again. It is
>> better to swap out those pages and create more disk buffers than leave them
>> resident and unused."
>>
>>
>> ---------------------------------------------------
>> PLUG-discuss mailing list - PLUG-discuss at lists.phxlinux.org
>> To subscribe, unsubscribe, or to change your mail settings:
>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss
>
>
>
> --
> A mouse trap, placed on top of your alarm clock, will prevent you from
> rolling over and going back to sleep after you hit the snooze button.
>
> Stephen
>
> ---------------------------------------------------
> PLUG-discuss mailing list - PLUG-discuss at lists.phxlinux.org
> To subscribe, unsubscribe, or to change your mail settings:
> http://lists.phxlinux.org/mailman/listinfo/plug-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.phxlinux.org/pipermail/plug-discuss/attachments/20180924/55bec0ea/attachment.html>