Request : Priority to firsts blocks of a file

Feature requests not specific to either the Mac OS X or GTK+ versions of Transmission
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PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

Hello !

I rode somewhere that BitTorrent can be used for streaming.
So, I though that it must be possible to download the "parts" (or "blocks") of a file from the first bit to the last one.

In Transmission, we can set priority to some downloads and/or some files.
I think it would be nice to be able to say to Transmission to try to download the firsts blocks of a file in priority.
That would give us the possibility to watch a video that is still downloading with VLC, for exemple. The main interest of DDL is that we can do that, and not with BT.

Is that idea silly ? Is that possible ? Can it be done with Transmission ?

Thanks !
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

Thank you ! I Didn't had seen that ticket.

In this ticket, it said that we can change the priority "by hand" in the file inspector. How can we do that ? I can't find it, I only see the possibility to change the priority of a file among the others.
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

So, if I understand well, the arrows of priorities I see next to the files names can be replaced to something else in order to activate the "download in order" option ?
Why are those 2 options not activated at the same time ? It can't be used at the same time ?
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

OK, so, the inspector option has nothing to do with my "request", then. ;-)
Is there any kind of problem that could come if we tell that a file should be downloaded in priority, and the blocks in order ?

The best would be that Transmission will try to download the firsts blocks of a file in priority, but not inevitably in order. For exemple, if it can have the blocks 1 to 17, the block 35 to 46 and the 55 to 76, it will download the blocks 1 to 17 in order, the 35 to 46 in order and, then, the 55 to 76 in order. But if it miss the blocks 1 to 17 and can only download the blocks 35 to 76, it will download them without waiting for the blocks 1 to 17 to be available. And if it discovers that the block 1 to 17 are available during downloading blocks 35 to 76, if necessary, it will suspend the download of those blocks to download the firsts ones.
blacke4dawn
Posts: 552
Joined: Sun Dec 13, 2009 10:44 pm

Re: Request : Priority to firsts blocks of a file

Post by blacke4dawn »

PierreOnTheNet wrote:OK, so, the inspector option has nothing to do with my "request", then. ;-)
Is there any kind of problem that could come if we tell that a file should be downloaded in priority, and the blocks in order ?
From a technical point of view, no but it goes against the spirit of bittorrent.
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

Against the spirit of BitTorrent ?
I though it was the creator of BitTorrent that had developed the Streaming over BitTorrent ?!
Can you explain me the spirit of BT ? I didn't had heard of it so far. :oops:
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

I think the ticket is talking about the files and not the blocks of a file. But it seems that the problem is the same.

If I understand well, downloading the blocks of a file "in order" is bad for the BitTorrent network ?
I think I understand why : if the file is downloading randomly, it's because it can be fully available on the network, but in pieces on different seeders's machines. Like this :
A is the first seeder, B has the first half of the file and C the second half. Even if A stops seeding, B and C can still have the complete file by seeding the half to each other !
Thank you, x190, I learned something.

BUT, if the file is shared by enough peers (say, 5 peers has the file completed), downloading the file "in order" is quite safe for the overall swarm health. In that case, Transmission would activate the option to download the blocks of a file "in order". That would be a HUGE feature for Transmission !
What do you think ?
gotozero
Posts: 2
Joined: Thu Mar 22, 2012 6:25 pm

Re: Request : Priority to firsts blocks of a file

Post by gotozero »

PierreOnTheNet,
That would be very nice!
If you find something, break the silence.
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

Sorry but I'm not doing anything to Transmission since I don't have any response from x190 : I'm not going to mess with others work until I'm sure to not break any "philosophy rule" of P2P or Transmission.

But thank you for your support : at least, I'm not the only one to think that it could be a good thing. ^^
gotozero
Posts: 2
Joined: Thu Mar 22, 2012 6:25 pm

Re: Request : Priority to firsts blocks of a file

Post by gotozero »

What phylosophy are you talking about.
In most popular Bittorent client - uTorrent >=3.0, that function works fine.
PierreOnTheNet
Posts: 8
Joined: Mon Feb 13, 2012 9:55 pm

Re: Request : Priority to firsts blocks of a file

Post by PierreOnTheNet »

I'm talking about the "phylosophy" that make the Transmission's devs to not implement this feature :
Why is this "feature" not implemented in Transmission?
Because it makes the overall swarm's health worse.
;-)
cfpp2p
Posts: 290
Joined: Sat Aug 08, 2009 3:14 pm

Re: Request : Priority to firsts blocks of a file

Post by cfpp2p »

I've patched a working model of "Priority to firsts blocks of a file" that tries very hard to keep a healthy swarm. Giving it lots of testing this works very well. Upload rates do not seem generally any worse than with a torrent's priority switched off. No stalled torrents and will not refuse pieces, always accepting pieces even with weak swarms and the highest level of priority chosen. As shown by the two images below.

Image

Image

It depends on the swarm health how much first blocks are downloaded. You can find out more about it by this:
http://sourceforge.net/p/transmissionda ... dc6d/#da45
https://github.com/cfpp2p/transmission/ ... e8e05c0861
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