Author Topic: qBittorrent downloads throttling  (Read 790 times)

eightwt

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qBittorrent downloads throttling
« on: April 27, 2019, 01:53:04 pm »
Using latest version of qBit downloads of >3gig start normally, then eventually die after ~25%. Graph looks like a sawtooth with download speeds going from 4MB/sec to a few KB/sec and back up again. Tried uTorrent and it works just fine, but I prefer qBit features. So the problem seems to be with qBit and not hardware or OS problems.

I tried to upload a screen shot but it would not work. Is this an issue with this forum?

Switeck

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Re: qBittorrent downloads throttling
« Reply #1 on: April 28, 2019, 12:40:00 am »
The speed problems in qBitTorrent seem well-commented at qBT's issues at Github:
https://github.com/qbittorrent/qBittorrent/issues/7954   [4.0.2] The unstable speed issue
https://github.com/qbittorrent/qBittorrent/issues/8284   Download going up and down (Mac)
https://github.com/qbittorrent/qBittorrent/issues/8579   Download speed jumping up and down on MAC
https://github.com/qbittorrent/qBittorrent/issues/8433#issuecomment-366487275      "As can be seen the upload 46 KIB/s has exceeded the limit 42 KIB/s temporarily and there was a peak at 55.3 KIB/s sometime during the half hour"
https://github.com/qbittorrent/qBittorrent/issues/8507   Erratic upload and download speeds

And there are cases where qBT ignores its speed limits, almost guaranteeing overloads and disconnects:
https://github.com/qbittorrent/qBittorrent/issues/6214
https://github.com/qbittorrent/qBittorrent/issues/6292
https://github.com/qbittorrent/qBittorrent/issues/6365
https://github.com/qbittorrent/qBittorrent/issues/6563
https://github.com/qbittorrent/qBittorrent/issues/7059
https://github.com/qbittorrent/qBittorrent/issues/7141
https://github.com/qbittorrent/qBittorrent/issues/7668
https://github.com/qbittorrent/qBittorrent/issues/7684   "qBittorrent says it's been uploading at ~100KBps average. In actuality, it's uploading ~450-500KBps (my maximum upload speed) as reported by both the operating system and router itself"

My guess is there's major issues in uTP handling by qBT/libtorrent:
https://github.com/arvidn/libtorrent/issues/2752   "The utp_stream.cpp code is in pretty serious need of cleaning up and modernisation as well. Perhaps such effort would tease out this issue."
https://github.com/qbittorrent/qBittorrent/issues/4284#issuecomment-269936135      Constant ~10% retransmits by uTorrent to qBT in tests using local loopback 127.0.0.1 and uTP often fails to reach 1 MB/sec. But if using TCP only, speeds hit >100 MB/sec!
https://github.com/Tribler/tribler/issues/2620      Understanding the impact of latency on Libtorrent thoughput

Major improvements should be appearing in qBT over the next few revisions, as it jumps from using libtorrent v1.1.12 to v1.2.x


As for this forum, did you try using attachments or some other way to paste screenshots here?

eightwt

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Re: qBittorrent downloads throttling
« Reply #2 on: May 01, 2019, 10:52:54 pm »
Thanks for the reply. I looked thru all your links, at least those that were still current, and found nothing that would explain this.

As for attaching a screen shot, the "Choose File" dialog will not attach or send my screen shot, or anything else for that matter, even though I can select it using the chooser. I'd send by regular email if I had a clue what the email address was :)

Switeck

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Re: qBittorrent downloads throttling
« Reply #3 on: May 02, 2019, 12:01:51 am »
Try reducing max connections per torrent to only 10-30 (10 while only seeding, 30 while downloading).
Also set global upload slots to 1/10th to 1/50th your max usable upload speed in qBT.
Beyond that, set upload slots per torrent to slightly less than max connections per torrent. (But at least 2 per torrent, or qBT will perform poorly.)

I don't expect these together to solve your problem, but maybe it'll reduce the problem slightly till an improved version of qBT comes out.