[Arm-dev] Using zram-swap

Robert Moskowitz rgm at htt-consult.com
Fri Oct 12 17:35:40 UTC 2018



On 10/12/18 1:24 PM, Fred Gleason wrote:
> On Oct 12, 2018, at 13:15, Gordan Bobic <gordan at redsleeve.org 
> <mailto:gordan at redsleeve.org>> wrote:
>
>> It depends on what you are running on that system. If you have 1GB of 
>> RAM and want to run a desktop environment web browser, that'll go 
>> pretty poorly without swap.
>
> So how does putting swap on RAM help that situation? You’re not 
> increasing the overall memory space by doing so, but merely 
> partitioning it into two different buckets (while also adding the 
> complexity and performance overhead of accessing the part that is now 
> ‘swap’).

See Gordon's earlier comment on Firefox's bad memory allocation. Zram is 
a big help there; I see this on my F29 system.

# free
               total        used        free      shared buff/cache   
available
Mem:        1022148      655520      107204 22284      259424      327636
Swap:        487304      253952      233352

# zramctl
NAME       ALGORITHM DISKSIZE   DATA  COMPR  TOTAL STREAMS MOUNTPOINT
/dev/zram0 lz4         475.9M 246.4M 109.1M 114.2M       2 [SWAP]

My mail server can be all over the place on memory and swap usage (it 
uses real swap file on sata) depending on what all the scanning software 
is doing and who is using roundcubemail.

So YMMV, and this should not hurt if your system does not need to swap.

# free
               total        used        free      shared buff/cache   
available
Mem:        2060396      189332     1189972 26432      681092     1766392
Swap:        982420           0      982420

# zramctl
NAME       ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS MOUNTPOINT
/dev/zram0 lz4         959.4M   4K   64B    4K       2 <swap>


I may switch this setup to a Cubeboard2 (1GB mem) from the Cubietruck.   
I have a number of C2 and only a couple CT, so if it does not need the 
memory...

>
> Cheers!
>
>
> |----------------------------------------------------------------------|
> | Frederick F. Gleason, Jr. |              Chief Developer         |
> |                           |              Paravel Systems         |
> |----------------------------------------------------------------------|
> |         A room without books is like a body without a soul.         |
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>
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