[maemo-users] OS2008 on n800 - Nice Job

From: Eero Tamminen eero.tamminen at nokia.com
Date: Wed Nov 28 10:55:25 EET 2007

ext Jonathan Greene wrote:
> On Nov 27, 2007 5:07 PM, Acadia Secure Networks
> <acadiasecurenets at aol.com> wrote:
>> its the OS2008 on the N800 faster because of software redesign or has
>> the hardware been reconfigured by means of a different software setting
>> to run at a higher speed than OS2007? I would assume the former but I am
>> not familiar with the details of the N800 processor.
> I believe the "limiter" has been removed and the N800 can now use the
> full CPU.  OS2008 has some efficiencies which let the CPU be used as
> needed to maximize both performance and battery life... much more so
> than in the previous editions.

The main reason why OS2008 is faster than OS2007 is that kernel now
supports Dynamic Voltage Frequency Scaling (DVFS).  When only CPU is
used, the frequency can be higher than in OS2007, when also DSP is used,
it needs to be dropped to earlier speed (which transition was a real
pain to get fast and reliable enough).  When neither is needed,
frequency can be dropped even lower which improves battery usage.

The kernel Flash memory de/compression uses now faster algorithm
which speeds up all disk accesses slightly (because the algorithm
doesn't compress as well as previous one, the rootfs is now more full).

Libjpeg is now better optimized (all these factors make e.g. image
viewer image loading significantly faster).

Some additional packages are now built with VFP (e.g. PDF reader is
faster because of this).  Because thumb & VFP don't work together,
this increased the rootfs size slightly too.

After the N810 release there was also a minor optimization to the N800
specific touchscreen driver which makes N800 response ~20ms faster.
I'm not sure whether this was included into the OS2008 beta release
for N800 yet.

	- Eero

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