How do torrent ratios work?

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josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

How do torrent ratios work?

Post by josephj »

I regularly see ratios - especially for uploads that are lower than I would expect them to be. And, they do not catch up later (as might be expected if it came from a tracker that was behind in updating it.) Below is a current example. Is this a bug? 640.2 is a lot more than 100% of 622.7.
tx2.png
tx2.png (8.2 KiB) Viewed 52366 times
TIA
Joe
lazybones
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Joined: Sun Jan 24, 2010 12:41 am

Re: How do torrent ratios work?

Post by lazybones »

If there are rare parts you could spend a lot of time trying to get the last ones, and thus are still uploading in that time frame. This will cause you to have a high upload ratio.
josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

Re: How do torrent ratios work?

Post by josephj »

Thanks. I don't understand your reply. From my perspective, I'm looking at torrent size in bytes and uploaded data in bytes. I don't see how time enters into it at all. Please elaborate.

Joe
lazybones
Posts: 220
Joined: Sun Jan 24, 2010 12:41 am

Re: How do torrent ratios work?

Post by lazybones »

You are sharing parts of the file you have to many other users so you may upload the same part to many people over and over while you are still downloading.
josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

Re: How do torrent ratios work?

Post by josephj »

x190 > that makes sense, but that's a whole lot of errors on every torrent and my line - at least - is pretty clean.
Don't tell me ... You're using the Mac version ... I don't get any cool displays like that in Linux.

lazybones > It really shouldn't matter what part of the file I am sharing and whether it happened before or after I was done downloading. I'm sure it happens in both cases anyway. If what part of the file I was sharing mattered, how could my ratio ever get beyond 100% - that's sharing the whole thing? In a p2p environment, only the number of bytes served really matters because each peer serves whatever they have in a relatively random manner to maximize the chances of every peer having something to offer to every other peer. I am sure that data I have uploaded while still downloading contributes directly to the ratio. I have seen it happen on almost every torrent.

Joe
josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

Re: How do torrent ratios work?

Post by josephj »

Lately (2.31), the ratios seem to be much closer to what I would expect. I believe something got fixed.

Thanks.
Jordan
Transmission Developer
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Re: How do torrent ratios work?

Post by Jordan »

joesephj,

The ratio is based on bytes uploaded divided by bytes downloaded. Yes, if you were to share the entire file with one user your share ratio would be 100%.

You seem to be asking how a share ratio could be over 100%. The answer is simple. You're sharing with a lot more than 1 peer, so you have lots of chances for uploading more bytes than you've downloaded. So, your ratio can easily go over 100%.
blacke4dawn
Posts: 552
Joined: Sun Dec 13, 2009 10:44 pm

Re: How do torrent ratios work?

Post by blacke4dawn »

Jordan wrote:You seem to be asking how a share ratio could be over 100%. The answer is simple. You're sharing with a lot more than 1 peer, so you have lots of chances for uploading more bytes than you've downloaded. So, your ratio can easily go over 100%.
The way I interpreted it was that he asked why it didn't list a 100%+ ratio when it shows that that torrent has uploaded more bytes than downloaded.
josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

Re: How do torrent ratios work?

Post by josephj »

@Jordan I took the number of bytes uploaded and divided it by the number of bytes in the torrent (both as reported by Transmission) and did a simple division and got a different (higher) result than what Transmission was reporting. At first, I thought this might have something to do with MB vs. MiB, but since both numbers use the same units, that should not be an issue.

@blacke4dawn Yes, but for any ratio, not just for 100%.

As I posted earlier, the results now are very close - not far enough off to matter. Now it could just be a precision (of display) issue, etc.

Joe
josephj
Posts: 96
Joined: Wed Mar 25, 2009 6:46 pm

Re: How do torrent ratios work?

Post by josephj »

I'm still using Transmission and still obsessing about the ratios. :)

I finally figured out that the seeding ratio is uploaded/total downloaded and not uploaded/torrent size.

This is obviously not a big deal, but I wonder why the decision was made to calculate it that way. How much I had to download to get a full copy (with bad blocks, etc.) doesn't seem like it would be relevant to me or to anyone else.

Thoughts appreciated. (especially if they don't require use of the military alphabet LOL)
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