lubuntu-qa team mailing list archive

[Nio Wiklund <nio.wiklund@xxxxxxxxx>]

Hi Mélodie,
I'll reply inline
Best regards
Nio

On 2013-10-11 13:23, JM wrote:
> On Fri, 11 Oct 2013 10:47:21 +0200
> Nio Wiklund <nio.wiklund@xxxxxxxxx> wrote:
> 
>> [Results after installation at the end]
>>
>> -------- Original Message --------
>> Subject: final Lubuntu i386 desktop live
>> Date: Fri, 11 Oct 2013 09:06:30 +0200
>> From: Nio Wiklund <nio.wiklund@xxxxxxxxx>
>> To: lubuntu-qa@xxxxxxxxxxxxxxxxxxx <lubuntu-qa@xxxxxxxxxxxxxxxxxxx>
>>
>> Hi!
>>
>> I have started testing the final Lubuntu i386 desktop live session, and
>> found the bugs 940919 and 1213837.
>>
>> Slow but no freeze with low RAM
>>
>> I limited RAM to 256 MB, and it worked. no freeze while I installed htop
>> at the same time as I opened Firefox. I could run htop and watch
>> swapping. Firefox was extremely slow, and you hardly browse to
>> ubuntu.com (I saw the top of the page but could not scroll, even after
>> waiting for minutes). So live session with 256 MB is no go with this
>> version in this computer
>>
>> http://www.toshiba.se/laptops/satellite-pro/c850/satellite-pro-c850-19w/
>>
>> if you want to browse the internet. I could close Firefox and see the
>> RAM being released.
>>
>> Maybe old hardware and an installed system eats less RAM, so it might
>> work better with low RAM, but the main reason of this test was to
>> stress-test zRAM.
>>
>> Best regards
>> Nio
>> ------------------------
>> Hi again,
>>
>> Installation worked with 512 MB RAM. Not the same freeze as with beta2,
>> but the restart after installation was not clean. It froze with only
>> back-light on, and I had to shut off with the button. After booting the
>> installed system worked as it should.
>>
>> Firefox offered to install flash 'Plugin Finder Service 2', but it got
>> stuck forever (a bug?). But sudo apt-get flashplugin-installer works and
>> lets me watch youtube videos. Firefox works reasonably well as installed
>> with 256 MB RAM (much better than live in the same computer).
>>
>> I did not identify any of the old bugs.
>>
>> Best regards
>> Nio
> 
> Hi,
> 
> I would have liked to read from your tests if the machine slows down by swapping too early
> while some memory is still available or if it uses most of the physical RAM before doing
> so. You could see it by having htop running in a console and keep on eye on proc and ram
> use at the top of the console while starting and using applications.

I *was* watching the memory usage and process activity with htop :-)

It was swapping before the memory was fully used (Lubuntu is always
doing that, with or without zRAM). I have not changed the swappiness
from the default value.

> I have done tests with ZRAM, in an iso I am doing (a personal remix done with
> ubuntu-builder) and have not finished yet. It consists in once having the configuration
> default provided by the zram-config package, then in another ISO switch to the
> configuration I have described before. 
> 
> I still have one test to do which could make a difference.
> 
> Linux kernels have been known to swap to disk too early since many years, and the
> following configuration is a mean to limit the too early swappiness.

I think some (or many) people want it that way, to have a margin, when a
large chunk of RAM is needed, and I have followed discussion threads
about swappiness. Some people claim there should be different settings
for servers compared to desktops & laptops (more swappiness for
servers). I have not tested with different swappiness, so I have no own
experience.

> So the test I want to do at last will consist in using the default zram-config
> configuration and add just this: 
> 
> 
> **********
> vm.swappiness=0 
> vm.vfs_cache_pressure=50 
> 
> # Uncomment the next line if we are running a laptop 
> # vm.laptop_mode = 1
> 
> **********
> 
> as a file such as 50-local.conf in /etc/sysctl.d.
> 
> I wanted to try in Lubuntu but ubuntu-builder has not been able to redo a bootable ISO
> from from the build directory after I added the file in the Lubuntu filesystem and
> generated a new ISO.

I can try it in an installed system. It is easier and also more
interesting for me :-P

-o-

I think the ramdisk makes it harder for the memory management in the
live system, which could explain why it choked earlier than the
installed system with 256 MB RAM.

> If you have some means of testing this setup in your machine it could be interesting. (As
> live I fancy it could be done with an install to USB with USB Creator and then having a
> persistant mode, add the file, and reboot to the persistant mode once more to test the
> setup, in your install you could just add the setup and see while using and with htop if
> that makes a difference after some time using Firefox or else?)
> 
> What I don't know yet either is if having zram module loaded and at work increases the
> linux kernel swappiness tendency or if it is totally unrelated : I had never wondered
> about it so far.
> 
> Regards,
> Mélodie
>