derek at pointerstop.ca
Thu May 14 20:15:58 BST 2009
Goh Lip wrote:
> I have 2 GB RAM, had 7.5 GB swap (yes, some time ago partitioned my
> disk, thought it safer than sorry, still no regrets, have more disk
> space than I could use).
A perfectly sound strategy these days.
> Jaunty 64
> KDE 4.2.3
> Linux 2.6.28-11
> Noticed at system monitor (always running), that my swap usage is ALWAYS
> zero, whatever I do, Gimp, Firefox, Kaffeine all running.
> Checked /etc/fstab to make sure swap is there, enabled and on, (swapon
> -a); even when flash 10 freezed temporarily firefox, swap is still zero.
> Is it because swap is not needed?
It's either because swap isn't needed or the monitor you're using is buggy
> Can my computer can handle all this without swap?
I wouldn't have thought so. I have 3GiB real memory (still trying to figure
out why it isn't 4, as everything I've read says I just need to use the PAE
enabled kernel to use all 4GiB) and it's rarely using more than 2GiB of
_virtual_ memory, but still some of that is always in swap space. Right now
I am using less than half my real memory, but there's still 700K of swap
> I also note though, that my RAM is never at 100% and my
> processors were never at 100%. (Flash 10 freezes 1 core at 100%, the
> other never at 100 %)
Then you probably really aren't using the swap space. Incidentally things
like flash are why I love dual core processors. It's _really_ nice finally
to actually be able to have a responsive system when something goes amok and
hogs 100% of a CPU.
> Next, suspend to disk, (now I know the distinction from suspend to RAM,
> thanks). Are they useful only for laptops, where battery conservation is
> desired? What purpose would it serve for desktops?
Well, I rarely use the laptop battery, but I always use hibernate - why shut
down, when you can hibernate? I always hibernated my Windows Desktop
machines, too. That becomes less of an issue as boot & shutdown times are
optimized, while memory sizes increase - it can take almost as long to
hibernate/resume as to shutdown/restart. I also have environmental
objections to leaving home computers on 24/7.
> Indeed, if we have suspend to RAM in laptops, what advantage would
> suspend to disk have? Won't battery consumption be lower if disk is
> actually off?
Actually, the power consumption of the disk is probably irrelevant. With
suspend-to-ram, the disk _will_ be shut down. With suspend-to-disk, the
whole system is turned off. The difference is in the power requirement for
the RAM and whatever else can't be turned off while the machine is
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