[maemo-developers] [maemo-developers] Unreliable Large Network Transfers

From: Frantisek Dufka dufkaf at seznam.cz
Date: Fri Dec 15 09:57:26 EET 2006
Mike Lococo wrote:

> I'm finding that large (>200MB) transfers of data via the wifi network 
> are extremely unreliable.  They start out running at a reasonable speed 
> (350KB/sec-600KB/sec), but within a few moments slow to less than 
> 100KB/sec.  The rates become very erratic, and the device GUI becomes 
> very unresponsive.

Are you sure network is a problem? Are you writing data somewhere? Both 
MMC card and iternal flash are really slow when writing. I had similar 
problem when writing to MMC card. First it is fast because data is 
buffered in RAM but then RAM is filled and as you say 'GUI becomes very 
unresponsive'. You can use 'top' in osso-xterrm to see cpu usage. If it 
is mmcqd of something like that then it is MMC writing. Enabling 
multiblock writes helps (a bit experimental feature).

Only when multiblock writes in MMC driver are enabled then wi-fi driver 
really becomes a bottleneck. It theory it should be the fastest way how 
to get data into the device (g wlan does normally > 2MB/s speeds) but 
sadly only ~600kb/s is reality with N770 and current driver. I wonder 
where exactly the bottleneck wih wi-fi is (hardware of software).


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