I/O related N900 unresponsiveness?
 

Hello all

Every time I leave the Application Manager in the background when it is updating or installing new software the N900 becomes locked up for a few seconds. Not even notifications can be dismissed for a while. Then everything goes back to normal.

The lock-ups also happen when new emails are being downloaded in background.

Here is a possibly related thread:

http://talk.maemo.org/showthread.php...ponsive&page=3

From reading other threads, I'm guessing that it might be related to situations where there is heavy I/O at the same time the swap partition is being used.

I was wondering if disabling the swap on the eMMC and enabling it only on the microSDHC could make things better, because of the lower device contention.

Does anybody have any experiences with this?

Re: I/O related N900 unresponsiveness?
 

I'm not an expert, but when this happens I'm normally quite convinced it's some sort of configuration error.

Something is trying to read some dot-files and failing, which causes locks.

Reflash root and emmc - and don't restore settings and see if that makes a difference.

Re: I/O related N900 unresponsiveness?
 

Hummm. Good hint. I've already reflashed root, but not the eMMC. Do you know of any log files i might be looking at? I want to try to fix this before having to reflash everything again...

Re: I/O related N900 unresponsiveness?
 

You're mentioning app manager, while I notice problems with general device responsiveness after ~4-5 days of uptime. What I see often is that performance drop happens usually when swap usage passes 20-25% of total use, roughly. One side of things are applications leaking memory, which could be identified by running sp-endurance snapshots (some of these leaks were fixed in PR1.2, but not all), second could be indeed swap space using physically the same memory as storage, hence degrading overall performance.

I've recently wiped one of my MicroSD cards, created 700MB swap partition and mounted as swap space in N900. To be honest, I haven't noticed any particular difference and after few days of uptime device got unbearably slow again, so reboot had to be done. However, in the meantime I've got much faster class 6 card, created swap on it and put into device. After 2 days of uptime it's hard to tell difference for sure, I'd need to work with it a bit more, but honestly - I don't think just putting swap on MMC should make a *huge* difference.

What is more important, I reckon, is identifying memory hogs and killing them off on regular basis in order to preserve memory (inculding swap) resources, hence keep more-or-less good overall performance. I'm going to observe things over the next few days and possibly create a script that would run overnight and kill off the major hogs without rebooting the whole device.

Re: I/O related N900 unresponsiveness?
 

I have noticed that when the swap file approaches 200MB, thats when things start getting bad.

Also using a class 4 microsdhc for swap was a disaster for me.

The N900 also devotes lesser number of data lines for the microsdhc relative to the much faster emmc.

Re: I/O related N900 unresponsiveness?
 

Yes, that's pretty much same amount I notice when device gets very slow.

Other notable (imho) thing is that device gets unbearably slow mostly at times when browser(d) is running. Browser is generally a huge resource hog, which can be best seen in apps like Conky. Once you're about to finish long'ish browsing session and close the last remaining browser window, open up Conky and watch what happens after that last browser window is closed.

I've only used class 2 card before, now testing with class 6 but to be honest - I can't see a great deal of difference, if any, so far.

Re: I/O related N900 unresponsiveness?
 

That usually happens when you install some sort of stuff on the device that runs in the background (eg. widgets), and has memory leaks.

Re: I/O related N900 unresponsiveness?
 

Well... that's pretty much what I've already said in my post.

Re: I/O related N900 unresponsiveness?
 

If your running the App Manager in the backround, it does push a popp up notification (a yellow one), this hangs the device for all intents and purpouses untill its touched, or you wait a while.

Re: I/O related N900 unresponsiveness?
 

After nearly ~2 weeks using my N900 with swap on external memory card (first few days on class 2 card, then class 6 card) I must say I did feel substantial performance degradation, especially while using browser, which seems to using swap space a lot. I am now switching back to normal setup with primary swap partition on internal eMMC to see how it compares.

Re: I/O related N900 unresponsiveness?
 

I wish there could be a "widget shortcut" application. Instead of placing the widget on the desktop, one could place a shortcut for it.

This could be handy for things that you don't use all the time (pedometer, recaller, etc). They won't stay active until you start it.

Or maybe just provide not-widget version of the applications...

Re: I/O related N900 unresponsiveness?
 

Also confirming that swap on an external microSD causes serious degradation after a few days of usage. I had a 2GB partition in conjunction with the 768MB and would be huge delays in the UI after less than a day of heavy usage that required swapping.