Re: [gentoo-user] zram / compcache, anyone?

[Pandu Poluan]

On Oct 13, 2011 8:32 PM, "Florian Philipp" <lists@×××××××××××.net> wrote:
>
> Am 13.10.2011 03:52, schrieb Pandu Poluan:
> > Just stumbled upon this blog:
> >
> > http://www.webupd8.org/2011/10/increased-performance-in-linux-with.html
> >
> > anyone got any experience with zram/compcache on Gentoo?
> >
> > Rgds,
> >
>
> Hmm, it seems like my reply was eaten by the mail server. Apologies if
> you receive this twice:
>

In addition to "the dog ate my homework", now we have a new excuse, "the
server are my document" :-D

Ah, progress ;-)

> I use it on my laptop (4GB RAM, typically 1-2GB swap used). It
> works pretty well but I can't give you any hard figures.
>
> I wrote my own init script for this. I can share it if you want.
> Otherwise the sunrise, betagarden and mv overlays offer ebuilds for it.
> I think the mv version is closest to mine.
>

What makes the proliferation of ebuilds?

> What has been pretty confusing is that there are two versions: The
> original one from Google(?) and the one in the mainline kernel. They
> have different APIs (hint: if you have a userland tool instead of
> manipulating /sys, it is the original version) and only the original
> version can use a swap device as an additional backend for
> uncompressable pages. With the mainline version (which I use), you can
> only use zram as an additional swap device and give it a higher priority
> than your normal swap.
>

In the kernel? What .config knob should I twiddle?

I do prefer having zram support in the kernel.

> /etc/fstab:
> /dev/zram0 none swap sw,pri=1,discard 0 0
> /dev/sda7 none swap sw,pri=0 0 0
>
> Only drawback so far: When zram is full, putting the laptop into standby
> takes longer, maybe 15s compared to 3s without. Sometimes this can lead
> to timeouts and the kernel aborts the suspend operation with an error on
> dmesg. Reattempting it then succeeds.
>

Point taken. Do you think it's worth the slight annoyance?

Rgds,