[ltp] X200s, 4 RAM 64 bit or not

[birger]

I have seen advice that the 64-bit kernel is more memory efficient than
32-bit even with just 1GB RAM because of the way it handles internal
structures. The only problem with going 64-bit would be user space
applications that *could* use more memory. They shouldn't really do
that, but some may. Also there is the far more efficient use of
registers in the compiled code that should give a speed improvement.

Beware of the file IO buffering bug that I think still affects 64 bit
kernels. If you write to 'slow' devices like memory sticks 64 bit linux
may allocate way too much memory to file system buffering. This can be
fixed by setting 2 kernel variables:
vm.dirty_background_bytes=104857600
vm.dirty_bytes=209715200

This limits the amount of buffering to the max a 32bit kernel would
allocate with 1GB ram or more. A fix for this is being discussed by the
kernel people.



On on., 2014-06-18 at 16:07 +0200, Uwe Brauer wrote:
> Hello
> 
> I upgraded to 4 RAM and I am running Kubuntu 10.04, trinity with PAE
> enabled. I am thinking to switch to 64 bit, but since still the majority
> of applications is 32 bit I am not sure that it is worth the effort. 
> 
> Can somebody advice me please?
> 
> thanks
> 
> Uwe Brauer