Author Topic: Other torrents drop out when a fast seeding torrent is added.  (Read 2996 times)

saywhat

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Other torrents drop out when a fast seeding torrent is added.
« on: February 20, 2018, 05:18:46 PM »
If you could look at this speed graph: https://i.imgur.com/ph99QIF.jpg

Before arrow 1 i have three torrents downloading. At arrow 1 I added a linux torrent which is a fast seed and as you see the download rate increases (for the linux torrent) but at the same time the other downloads drop out  completely or reduce to a tiny speed. At arrow 2 I cancel the fast linux torrent and you can see downloads drop to zero for quite a while until at arrow 3 the original three torrents start up again.

So is this normal? If not any ideas what I could do to 'stabilise' the downloads? Also I'm using a VPN just in case that has any bearing on this.

Thanks for any help.

Switeck

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Re: Other torrents drop out when a fast seeding torrent is added.
« Reply #1 on: February 20, 2018, 09:15:37 PM »
Probably a bug.

Also, definitely aggravated by having lots of connections and half open connections active at once.

The VPN could even be an issue, if it's not a lot faster than 15 mbit/sec.

Henry63

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Re: Other torrents drop out when a fast seeding torrent is added.
« Reply #2 on: February 20, 2018, 09:54:08 PM »
Some Linux seeders have horrendous bufferbloat and TCP will effectively DOS you with resends. I used wireshark to figure out why I was seeing high packet loss while downloading come Linux torrents myself. Turned out that some subset of the seeders had latencies up in 3,000ms rang. TCP assumed the packets were lost, but really they were just greatly delayed. Most TCP stacks do not rate limit resends. Nearly 50% of all of the packets I was recieving where duplicates.

My work around was to limit TCP transfer to 3/8th of my bandwidth. Even if 50% of the packets are dups, that would only be 6/8ths. uTP does not have this issue as it is latency sensitive.

See if limiting TCP downloads in the settings works for you.

saywhat

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Re: Other torrents drop out when a fast seeding torrent is added.
« Reply #3 on: February 21, 2018, 07:22:17 PM »
See if limiting TCP downloads in the settings works for you.

I'm not sure how to do that as I don't see anything specific to TCP settings alone?

P.S. I see this post has 990 views! So it must be a fairly common issue.

Henry63

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Re: Other torrents drop out when a fast seeding torrent is added.
« Reply #4 on: February 22, 2018, 01:22:29 AM »
Seems I set the global speed limit to 3/8ths, then I unchecked uTP from the limit. I'm still using 3.3.16