maemo.org - Talk - Using Micro SD Card as Virtual Ram on Nokia N900?

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- - Using Micro SD Card as Virtual Ram on Nokia N900? (https://talk.maemo.org/showthread.php?t=42357)

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

I have a Transcend class 6 and I've added a swap partition on it now. I'm not thoroughly impressed yet.

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

guys, i would like to try this. has anyone seen any BIG improvements so far?

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

what objective benchmarks could be used to compare the different cards? should the main swap file be turned off in favor of the microsd swap?

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

The speed boost for me has been quite small, but I'd say it's a worthwhile mod if you have the extra space.

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

i did this mod and made swap off for emmc and on for microsd... with emmc swap i could apps opening slowly after 5 apps but with swap on microsd it was pretty smooth...

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

omg this is best invention since fried rice, I mean cmon the swap memory is slow so no problem add more 2gb ram =sex

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

Quote:

Originally Posted by rewt (Post 496825)

For those who need more VM, and wish to use their entire MicroSD card for this purpose:

(WARNING: This will erase the entire MicroSD card, or worse, some or all of your internal memory if you mistype the device name.. If you plan to proceed, I recommend that you have some idea what you are doing)

In x-term:

Code:

sudo gainroot

mkswap /dev/mmcblk1p1

swapon /dev/mmcblk1p1

The last line will have to be rerun each time your device is rebooted, unless you add an init script to run it.

it says invalid arguement

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

If creating an extra swap on the MicroSD does make a noticeable difference, can someone actually make a simple app with a GUI to make this happen without needing to type all the commands? (like partitioning the microsd, setting the swap etc) Would be pretty cool. I'm no dev unfortunately. =P

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

Quote:

Originally Posted by jakiman (Post 762892)

Yeah I think there should be this one app,

where there are 3 options

Battery Saver=Titans hunger clock setting 0-600 mhz with 1gb ram
Moderate=Titants 500-800mhz with howmuch swap on the sd you got
Extreme=500-1ghz and how much swap you got

Re: Using Micro SD Card as Virtual Ram on Nokia N900?

Hi!

Was wondering about my N900 often being very slow and unresponsive (and trying to make up some easy explanation to my wife how can it it take 2-3 minutes to silent the alarm of my new state-of-the-art mobile computer-phone-thingy when it happens to ring half an hour too early). Noticed that is because of IO waits caused by swapping. Sure I got dozens of apps but hey isn't that what this device has been built for. Wondering how to improve it so bumped at this thread going straight into the point.

There were already step-by-step instructions for creating those partitions but as I happened to be MUCH more comfortable with fdisk than sfdisk and there was fdisk installed with the Easy Debian package, did the tricks with that. Also, other parts of that process were scattered all around this thread and the internet so decided to do some wrap-up.

So, here's how to:

- Back-up whatever needed from the card, it WILL be empty after this procedure.
- Close anything that might use the uSD card
- Run Debian chroot (install Easy Debian if you don't have it already)

- On the console:
---
umount /media/mmc1
fdisk /dev/mmcblk1
p #print partition list, check it's the correct device, see how many cylinders you got and how many bytes per cylinder.

d #delete partition
<enter> #partition number, default=1

n #new partition
p #primary
<enter> #start cylinder, default=1
1900 #end cylinder, my 16GB card has 1949 cyls and 49 happened to be pretty close to 384MB which should be fine so 1900 can be used for the data partition

n #new partition
p #primary
<enter> #start cylinder, default=first non-allocated
<enter> #end cylinder, end of device = allocate the rest for swap

t #change partition type
1 #partition number
b #vfat

t #change partition type
1 #partition number
82 #Linux swap

p #print table, check everything is OK

w #write table

<open back cover> #Re-seat the card to make kernel forget the old parameters
<remove card>
<insert card>
<re-insert back cover>

mkswap /dev/mmcblk1p2 #prepare the swap partition
swapon /dev/mmcblk1p2 #enable the swap partition
free #check that you now have more swap
mkfs.vfat -F 32 /dev/mmcblk1p1 #format main partition
mount /media/mmc1
---

Now test copying something into your uSD card to see it works properly.

The swap partition won't be automatically taken in use after reboot, use a startup script like this one to make it automatically.

Did this only today so don't have much experience yet but so far feels more like a new device than a mere performance improvement! Trying to abuse it to make IO waits hit the roof but no, can't get them over 30% so haven't managed to make it unresponsive. I'd guess it'll be worse after a couple of days uptime but looks promising anyway.

My card is a Nokia 16GB class 2 card so shouldn't be that fast but measured with hdparm -tT ("apt-get install hdparm" with Debian chroot) to be actually a bit faster than a no-name class 6 8GB card. Hdparm gives about 15MB/s non-cached read speeds for this 16GB card and about 20 MB/s for the internal /dev/mmcblk0p3 swap so the card is clearly slower but still helps a lot.

Great thanks guys for the groundwork so far!