Public bug reported:

Binary package hint: ubiquity

Previously, I suggested that we should "Support 256MB machines in
Ubiquity" by adding compcache (bug #193552). This has been implemented.
Since then there has also been added an option to the boot screen to
install Ubuntu without loading the full Gnome environment. Using this
new option it is possible to install Ubuntu using Ubiquity onto 128MB
machines if we set the compcache/ramzswap device to 128MB.  However
setting this manually is difficult and the user should not be expected
to know what a compcache is.

I propose that we automatically set the compcache to 100% or 128MB of
ram for machines with less than 200MB of ram when booting straight into
ubiquity. This should allow Ubiquity installs to "just work" on machines
with as little as 128MB of ram.

I note that:
1) 128MB machines are still in operation, work quite well with e.g. LXDE.
2) Compache tends to achieve a 4:1 compression ratio [1], so if the compcache 
device is the same size as physical ram it will only use up about 25% of ram, 
so a 100% sized compcache is reasonable.
3) Even if the primary workload involves filling ram with random data, a 100% 
compcache device will use significantly less than 100% of memory since filling 
ram with random data will still cause system processes to be evicted, and these 
processes will compress well [1].
4) Despite the above I am not convinced that using 100% sized compcache is a 
good idea when it is not needed. In principle the compcache device only 
allocates memory on demand so it is plausible that 100% compcache would improve 
performance. However the back-of-an-envelope benchmark [1] I performed 
suggested that using more than 50% compcache could reduce performance. Until 
better benchmarks are available, I see little point in switching the default 
liveCD compcache size to 100% (50% may be a good idea since it helps prevent 
OOM kills and doesn't seem to harm performance, but there isn't a compelling 
argument to switch to 50% unless it is needed to prevent OOM kills messing up 
the primary functions of the LiveCD.)

[1]  http://code.google.com/p/compcache/wiki/Eeepc701

ProblemType: Bug
Architecture: i386
CheckboxSubmission: 404bd18599e0899eb2769ef0d7f6c695
CheckboxSystem: 6944d89cd962d3dec0d4098e584fb8ff
Date: Wed Jan  6 20:28:11 2010
DistroRelease: Ubuntu 9.10
Package: ubiquity (not installed)
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=en_AU.UTF-8
ProcVersionSignature: Ubuntu 2.6.31-16.52-generic
SourcePackage: ubiquity
Tags:  ubuntu-unr
Uname: Linux 2.6.31-16-generic i686
XsessionErrors:
 (gnome-settings-daemon:2210): GLib-CRITICAL **: g_propagate_error: assertion 
`src != NULL' failed
 (gnome-settings-daemon:2210): GLib-CRITICAL **: g_propagate_error: assertion 
`src != NULL' failed
 (nautilus:2398): Eel-CRITICAL **: eel_preferences_get_boolean: assertion 
`preferences_is_initialized ()' failed
 (polkit-gnome-authentication-agent-1:2437): GLib-CRITICAL **: 
g_once_init_leave: assertion `initialization_value != 0' failed

** Affects: ubiquity (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 ubuntu-unr

-- 
Support 128MB machines in Ubiquity.
https://bugs.launchpad.net/bugs/503779
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