Active Topics

 


Reply
Thread Tools
Posts: 2,225 | Thanked: 3,822 times | Joined on Jun 2010 @ Florida
#71
Hi, I suspect this is a bug that may have began fundamentally before I subjected my N900 to these kernel tweeks. However, shortly after doing so, I developed a "symptom" in the form of the N900 crashing/rebooting spontaneously when dealing with very specific UI events - namely, selecting chunks of text with Home/End/PgUp/PgDown + Shift while the system is under medium to heavy multitasking load. My N900 has the aforementioned keys mapped to FN+Left/Right/Up/Down, so it's Shift+Fn+Arrow key.

There are other rare reboots without such presses but that's where I noticed it the most. I've been fiddling with some of the kernel parameters to see how I can get the best of both worlds - I suspect that what it is is some combination of having really low-and-easy-to-reach I/O locks, plus the RAM-heavy environment of multitasking.

To be fair I didn't originally implement all of the tweeks suggested here: I used my own marginal knowedge to try to find a middle ground between the hawaii tweaks (I don't like to call them swappolube tweaks without first pointing out that they came from hawaii) and this.

But in the meantime, I want to ask: the people who are benefitting from these mods, and you using your N900 for heavy multitasking, and if so, what kind? I/O heavy multitasking, processing-heavy multitasking, memory heavy multitasking (keeping in mind that you can and probably will be heavy on all/some of them), and how would you describe your multitasking in more plain english terms? Lots of files/data loaded into ram, as in video/music/whatever playing or heavy document/file editing, heavy web-browsing, what? Because when I play youtube videos, copy/edit files and use ftp/ssh/vnc, I am mostly reboot safe. But it's when I push the system and then just lightly use interactive UI elements that involves text (the MicroB browser being by far the primary offender), and do heavy text selection primarily, that it goes and reboots.

I'm not quite sure what's going on, and it seems that rasing dirty ratios slightly, and the vfs cache at 200, and for all I know my N900 is just dying from some hardware bug (never overclocked), but it's definitely odd, and if someone else is having spontaneous reboots after having these mods installed that has similar usecases to mine (lots of using the N900 as my primary web browsing and posting-my-rants tool), might mean something, and can help come up with better optimizations that get the majority of the benefits of this without impeding other use cases.
 

The Following User Says Thank You to Mentalist Traceur For This Useful Post:
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#72
Originally Posted by Mentalist Traceur View Post
Hi, I suspect this is a bug that may have began fundamentally before I subjected my N900 to these kernel tweeks. However, shortly after doing so, I developed a "symptom" in the form of the N900 crashing/rebooting spontaneously when dealing with very specific UI events - namely, selecting chunks of text with Home/End/PgUp/PgDown + Shift while the system is under medium to heavy multitasking load. My N900 has the aforementioned keys mapped to FN+Left/Right/Up/Down, so it's Shift+Fn+Arrow key.

There are other rare reboots without such presses but that's where I noticed it the most. I've been fiddling with some of the kernel parameters to see how I can get the best of both worlds - I suspect that what it is is some combination of having really low-and-easy-to-reach I/O locks, plus the RAM-heavy environment of multitasking.

To be fair I didn't originally implement all of the tweeks suggested here: I used my own marginal knowedge to try to find a middle ground between the hawaii tweaks (I don't like to call them swappolube tweaks without first pointing out that they came from hawaii) and this.

But in the meantime, I want to ask: the people who are benefitting from these mods, and you using your N900 for heavy multitasking, and if so, what kind? I/O heavy multitasking, processing-heavy multitasking, memory heavy multitasking (keeping in mind that you can and probably will be heavy on all/some of them), and how would you describe your multitasking in more plain english terms? Lots of files/data loaded into ram, as in video/music/whatever playing or heavy document/file editing, heavy web-browsing, what? Because when I play youtube videos, copy/edit files and use ftp/ssh/vnc, I am mostly reboot safe. But it's when I push the system and then just lightly use interactive UI elements that involves text (the MicroB browser being by far the primary offender), and do heavy text selection primarily, that it goes and reboots.

I'm not quite sure what's going on, and it seems that rasing dirty ratios slightly, and the vfs cache at 200, and for all I know my N900 is just dying from some hardware bug (never overclocked), but it's definitely odd, and if someone else is having spontaneous reboots after having these mods installed that has similar usecases to mine (lots of using the N900 as my primary web browsing and posting-my-rants tool), might mean something, and can help come up with better optimizations that get the majority of the benefits of this without impeding other use cases.
I think that the random reboots its only because u don't have a 2nd swap space and hence the bandwith of the swap-vm-sub-system isn't as large as it can be. I did for myself a heavy uses of the device too but with the 2nd swap space and this tweaks i get a really responsive device.
 
Posts: 310 | Thanked: 383 times | Joined on Jan 2010
#73
Hey MT,

Mine's been rock solid with the config listed here. :/ I multitask heavily all the time and reboot about once a week for some reason or another.

I will admit that I stopped striping my swap as my tests from the other thread were somewhat bogus. In real-world scenarios I found swapping to the internal storage + SD was slower as:

a) it ties up the internal storage and
b) SD card is much faster for reads and writes.

I'm now swapping exclusively to SD (9mb/sec write, 17mb/sec read) and everything's stable and snappy.
 

The Following 2 Users Say Thank You to nightfire For This Useful Post:
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#74
Originally Posted by nightfire View Post
Hey MT,

Mine's been rock solid with the config listed here. :/ I multitask heavily all the time and reboot about once a week for some reason or another.

I will admit that I stopped striping my swap as my tests from the other thread were somewhat bogus. In real-world scenarios I found swapping to the internal storage + SD was slower as:

a) it ties up the internal storage and
b) SD card is much faster for reads and writes.

I'm now swapping exclusively to SD (9mb/sec write, 17mb/sec read) and everything's stable and snappy.
I don't know about a) but this isn't true for me when I stripe swap like u have suggested in ur 1st post:

/dev/mmcblk0p3 partition 786424 0 -2
/dev/mmcblk1p1 partition 639988 88092 -1

and SD card has prio -1 and is filled with 88 MB and internal has prio -2 and filled with 0 Bytes my device feels much more responsive. My 8 GB class 6 card is most likely similar in read and write to ur card. Also I'm using readahead of only 16 and nr_request of 1-4. One explanation can be that the bigger stripped swap space affects somehow the calculation of the swap function. The other is that I randomly and accidently choose a size of the 2nd swap and the 1st space together that match the 128 kb page limit but I'm really unsure. Is ur internal swap then disabled und useless waste? Anyway I got an error in my sfdisk program when it should count from 1 to INFINITY like told in the wiki about partitioning the sd card my program count from 0.

Last edited by epitaph; 2011-03-02 at 09:32.
 
Posts: 310 | Thanked: 383 times | Joined on Jan 2010
#75
Originally Posted by epitaph View Post
I don't know about a) but this isn't true for me when I stripe swap like u have suggested in ur 1st post:

/dev/mmcblk0p3 partition 786424 0 -2
/dev/mmcblk1p1 partition 639988 88092 -1

and SD card has prio -1 and is filled with 88 MB and internal has prio -2 and filled with 0 Bytes my device feels much more responsive. My 8 GB class 6 card is most likely similar in read and write to ur card. Also I'm using readahead of only 16 and nr_request of 1-4. One explanation can be that the bigger stripped swap space affects somehow the calculation of the swap function. The other is that I randomly and accidently choose a size of the 2nd swap and the 1st space together that match the 128 kb page limit but I'm really unsure. Is ur internal swap then disabled und useless waste? Anyway I got an error in my sfdisk program when it should count from 1 to INFINITY like told in the wiki about partitioning the sd card my program count from 0.
Hmm. According to that /proc/swaps you're only actually using one of the swap areas (SD). If you want them to stripe you have to set them to the same priority.

Your current setup is identical to SD swap only..
 
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#76
Originally Posted by nightfire View Post
Hmm. According to that /proc/swaps you're only actually using one of the swap areas (SD). If you want them to stripe you have to set them to the same priority.

Your current setup is identical to SD swap only..
O.k. it's not striping but conky is showing correct size of swap space ( 1,36 Gb ). What is this setup is called?
 
hawaii's Avatar
Posts: 1,030 | Thanked: 792 times | Joined on Jun 2009
#77
...he just told you that setup is SD on swap only. Set your internal swap to -1 and your SD swap to 0 or set them to the same priority to "stripe" across in a more equal manner.
 
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#78
Originally Posted by hawaii View Post
...he just told you that setup is SD on swap only. Set your internal swap to -1 and your SD swap to 0 or set them to the same priority to "stripe" across in a more equal manner.
Thanks for the answer. I told him that conky is showing correct swap space size and I've asked him what is this setup is named?
 
hawaii's Avatar
Posts: 1,030 | Thanked: 792 times | Joined on Jun 2009
#79
Because both partitions are currently active for swapping - hence why it is showing the sum of both added together. You have the internal set at such a "low" priority that nothing gets swapped because the "higher" priority one...takes priority.
 
Posts: 310 | Thanked: 383 times | Joined on Jan 2010
#80
Hey epitath,

There are two configurations:

What you have is like raid-0 "concat" mode. Basically, when your highest priority swap runs out of space (SD, because -1 > -2), it'll start swapping to the next highest priority swap area (internal).

Your total available swap space is the sum of these two.

This configuration is particularly useful when you have block devices of differing speeds (ie. compressed ramdisk and slow media) since you can tell the kernel to use the fast device until it's full, and then start using the slow device. It would be even more useful if the kernel could migrate infrequently used pages from fast->slow in the background, but I'm not sure if anyone has implemented it.

The other configuration is like raid-0 "striping" mode. When you have your swap areas set to the exact same priority, the kernel will interleave blocks between the two. This theoretically increases both read and write bandwidth, just as it does with striped raid-0, since the kernel can parallelize the writes, and some reads.

Like the "concat" configuration, your total available space is the sum of the two, though the "stripable" area (increased bandwidth) is equal to 2x the size of the smallest area.

Last edited by nightfire; 2011-03-03 at 17:44.
 
Reply


 
Forum Jump


All times are GMT. The time now is 02:53.