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Improved ways to suspend and hibernate a laptop under Linux (Linux.com)

[Posted February 16, 2007 by ris]

Linux.com revisits suspend and hibernate. "Last June I wrote about suspending and hibernating laptops under Linux. Since then a few things have changed -- thankfully, for the better -- so it's time to revisit the subject. Also, a few readers have responded offering suggestions for improving the suspend shell script I wrote back then, and I've incorporated these suggestions in a new version; unfortunately most of the comments are anonymous, so I can't give proper credit to their authors. The most important change since the last article is that laptops with multi-core CPUs are now the de facto standard. Intel Core Duo and Core2 Duo processors not only offer Symmetric Multiprocessing (SMP) functionality to mobile users but also consume less power, and thus produce less heat, than their predecessors."

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Posted Feb 17, 2007 1:32 UTC (Sat) by Duncan (guest, #6647) [Link]

I've been periodically trying suspend to disk (hibernate I guess) on my
dual Opteron workstation, using the in-kernel swsusp, for some time.
Until recently, it would often work shortly after boot, but not after
actually /using/ the system for anything practical.

Reading that article early this morning, before I went to bed, I decided
to see if it actually worked now. It DOES! At least it does if I shut
down KDE/X and turn off the network. I haven't yet tried it from KDE/X
with the network (including ntp) up, but in any case, I should at least
be able to script it now, as in the article. =8^)

Technically, that's no small achievement the kernel hackers have
accomplished, as not only do I have a dual Opteron (soon to be dual
dual-core, after my next upgrade), but I'm running 4-way md/mdp RAID
(0/1/6) and have only a 4 gig per spindle swap partition, while I've 8 gig
of real memory. It's taken some time, but is still really impressive that
they've actually gotten it working, shrinking the physical memory
footprint by half by kicking out the cache and buffers to make it fit in
the swap partition, first shutting down one CPU, shifting everything to
the remaining one, then quiescing and shutting it down, including the RAID
and LVM2, AND bringing it all back up without a hitch!

Now I can hibernate when I'm not using the computer instead of leaving it
on all the time, or having to wait for the full boot. I've waited a long
time for this, but it's still impressive! =8^)

Of course, I hadn't been testing all that often, as coming back up from a
bad suspend was rather painful, with the RAID-6 containing most of my
system working very slowly for a couple hours, as it re-synced itself in
the background. Glad it's all working now. =8^)

Duncan

Improved ways to suspend and hibernate a laptop under Linux (Linux.com)

Posted Feb 19, 2007 15:31 UTC (Mon) by mmarq (guest, #2332) [Link]

How about persistence ?

http://www.erights.org/data/serial/jhu-paper/upgrade.html
http://cap.anu.edu.au/cap/reports/report99/node25.html
http://www.cse.unsw.edu.au/~cs9242/03/lectures/persistenc...

That is, instead of *swap space* being an extention of the physical RAM, it could act like a persistent inclusive cache, like the L2 is for the L1 in Intel processors.

Of course there are issues, but i belive i havent read nothing exluding that possibility... even for Linux.

If the content of RAM, and some machine state and drivers, could be duplicated in swap space, hibernation can be much more simplified, and suspend to disk can be a snap !...

Improved ways to suspend and hibernate a laptop under Linux (Linux.com)

Posted Feb 19, 2007 15:44 UTC (Mon) by mmarq (guest, #2332) [Link]

"" If the content of RAM, and some machine state and drivers, could be duplicated in swap space ""

Perhaps duplicated is not the best word, but mirrored is better, i. e., if you have 4Gig of RAM plus 6 Meg of cache in each of 2 processors, you sould have to have at least a little more than 4,12 Gig of sawp space.