Re: [GNUnet-developers] speed of gnunet-download

[Christian Grothoff]

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On Tuesday 26 August 2003 03:48 am, Igor Wronsky wrote:
> On Tue, 26 Aug 2003, Marcos D. Marado Torres wrote:
> > > # ./gnunet-download -o "aliensong.zip" --
> > > Speed was    0.093 kilobyte per second.
> >
> > You can read at http://www.ovmj.org/GNUnet/faq.php3#speed the really
> > reasons why GNUnet is slow... Either way, the transfer rates you're
> > presenting are slower than expected...
>
> The aliensong suggested for downloading in the FAQ is .mpeg, not .zip.
> The consequence is that the .zip is very likely less well distributed
> than the recommended file and thus slower to download, especially
> if its located on some low-capability nodes only. I don't think we
> have ever seen what really happens with gnunet when some content
> is on say 20 nodes simultaneously (a typical real-life p2p situation),
> unless every node operator has bothered to dl the .mpeg, which
> I think unlikely.

The problem is more that the current code divides bandwidth too evenly among 
all the peers. Since only few will actually be able to respond *in time* 
given their own bandwidth constraints, you get a horrible throughput.  This 
is primarily caused by GNUnet dividing your say 5 kbps evenly by 20 peers, 
giving each peer less than 250 bytes per second. If you are not popular, 
peers will typically not spend more than half of their bandwidth on you (even 
if otherwise idle), which may give you 125 bytes per second, which is close 
enough to the 0.093 kbps you see. 

Either way, we're aware of the problem & working on a good solution. 

> Anyway, improving speed on bandwidth-limited nodes is on the
> TODO-list, but apparently we are more interested in playing
> around with the GUI. :(

Am I not allowed to have any fun??? :-)

C
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