Re: [Qemu-devel] [PATCH] hw/vexpress: set default block type to SD

[Aurelien Jarno <aurelien@aurel32.net>]

On Sun, Mar 17, 2013 at 07:51:00PM +0100, Paolo Bonzini wrote:
> Il 17/03/2013 01:04, Aurelien Jarno ha scritto:
> >                           | boot | install build-dep | build lm-sensors |
> >   ------------------------+------+-------------------+------------------+
> >   versatile               | 1:09 |             2:27  |             4:09 |
> >   versatile cache=wb      | 1:08 |             2:25  |             3:44 |
> 
> Strange, cache=wb should be the default.

I agree it's strange, maybe there were other effects, but I am sure when
I did the tests cache=wb the build time was clearly shorter.

> The real problem with SD is that it doesn't have a flush command, hence
> it cannot be made safe against power losses.  But the solution is to add
> support for virtio-mmio in those boards.
> 
> Paolo
> 
> >   vexpress                | 1:11 |             3:07  |             3:49 |
> >   vexpress cache=wb       | 1:07 |             3:07  |             3:47 |
> > 

Here the results are more consistent with the default being cache=wb.

I'll try to do the same tests on another machine to see if the results
are still the same.

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net