TuxOnIce in Ubuntu kernel?

[Andy Whitcroft]

On Sun, Oct 18, 2009 at 04:59:03PM +0800, Chow Loong Jin wrote:
> Hi Kernel Team,
> 
> I've recently been testing out TuxOnIce on my notebook, and was rather surprised
> to note the performance improvements over the kernel method/swsusp. (Less than
> half a minute to a functional desktop, with swap in dm-crypt/lvm).
> 
> On the same system, the kernel method and uswsusp both take 2-5 minutes to
> resume, depending on how much memory/swap usage I had prior to hibernating.
> While this might have been acceptable in the past, with Ubuntu's boot time
> getting shorter and shorter (the target is 10s, IIRC), I think it's time our
> hibernating/resuming time grew shorter.
> 
> Something I did notice in my tests is that for the same system, all three
> methods resumed from cryptsetup's password prompt to userspace in pretty similar
> time frames (<30s). However, for the kernel method and uswsusp, the system is
> unusable while it continues to swap out for 2-5 minutes. A user on a bug report
> once did some benchmarks by running `vmstat 1` and hibernating. The result was
> that the swapout rate was approximately 1MB/s after resuming. IMO this is rather
> suboptimal and could be improved much.
> 
> And hence my suggestions:
> 1) Switch to tuxonice for hibernate/resume (tuxonice-userui can be improved, and
> pm-utils already has support for tuxonice)
> 2) Improve (u)swsusp to read out more from the swap instead of unfreezing tasks
> prematurely and having the rest swapped out slowly.

It seems that the plan is to pull the good bits of Tux-on-ice into the
mainline kernel in an incremental manner over the next couple of releases.
We will need to monitor this for Lucid.

-apw