Best strategy to identify cause for large swap - or whatever it is that's making the system sluggish

Comments

• canedje Member

  December 2017 edited December 2017

  In this  discussion (see link) there is a solution to write a script for checking every night and if swap file is above 150Mb it will restart your Homey.
  For me it workes fine:
  https://forum.athom.com/discussion/comment/64670/#Comment_64670
  
• cbh Member

  December 2017

  Thanks - actually, I already tried it.
  However, if possible, I'd like to find the cause and look into the origin instead of having to reboot the system frequently...
• canedje Member

  December 2017

  cbh said:

  Thanks - actually, I already tried it.
  However, if possible, I'd like to find the cause and look into the origin instead of having to reboot the system frequently...

  I agree. I will follow this item to hopefully find a solution.
  my Homey did crash already once because of the swap size (i think)
• tb1962 Member

  December 2017 edited December 2017

  @cbh and @canedje
  
  You can loop through the installed apps like this:
  

  const apps = await Homey.apps.getApps( );
  
  let totalSwap = 0;
  _.forEach(apps, (app) => {
      totalSwap += app.usage.swapPss;
      console.log(app.id + ', pss: ' + app.usage.pss  + ', swapPss: ' + app.usage.swapPss + ', mem: ' + app.usage.mem + ', total: ' + (app.usage.swapPss + app.usage.pss));
  
      //console.log(a);
  })
  console.log('totalSwap: ' + (totalSwap / (1024*1024)) + 'MB')
  

  
  Now, i'am a little unsure what the meaning is of swapPss and pss. But as you can see the total of these values equals <mem>
  
  The last line (totalSwap is not the same as the swap you see in the system page. This is because this code only count the installed apps, not swap space used by Homey itself
  
  swapPss has something to do with swap space usage. Maybe someone knows enough from linux to explain what this is?
  
  
  
  
• djesko Member

  December 2017 edited December 2017

  when i asked about this before i got this link  https://www.linuxatemyram.com
  
  my swap is 300 and is running fine 
  
  
  
• tb1962 Member

  December 2017

  app.usage.pss + app.usage.swapPss is the same as app.usage.mem and (app.usage.mem / (1000*1000)) is the same as memory usage given per app on the system page. So I think swappPss is nothing special. It is the swap usage in bites. I was a bit misleaded by this info: https://stackoverflow.com/questions/9922928/what-does-pss-mean-in-proc-pid-smaps wich i did not understand completly
• cbh Member

  December 2017

  Well, even if https://www.linuxatemyram.com/ says my RAM is fine, the problem still is, that somethings going on at the system is getting sluggish...
  It might be, that the size of the swap file isn't part of the problem, only a symptom and that rebooting cleans up stuff - and that is just a co-incidental thing with the swap file - and that's fine with me - wich leaves me to rephrase the question:
  Best strategy to identify cause for large swap - or whatever it is that's making the system sluggish?
• tb1962 Member

  December 2017

  @cbh
  
  Well, another thing you could look at is de app.usage.cpu. This value should be as low as possible (between 0... 1) but it can be more than 1. That doesn't have to be a bad thing but if that's for a longer periode of time maybe you should restart that app.
  
  In Settings -> System -> Stuff for geeks there is a loadavg. This shows 3 values. The first is the current cpu load and the last is the average for the last 15 minutes. You could also take a look at these values.