FAQ Rtorrent 16 fills my upload and everything else on the internet lags

[Silas Mariusz]

Symptoms

• Web pages, video calls or games slow down while torrents seed or download.
• The Upload figure stays close to the upload speed of your internet plan.

Cause
Upload speed is unlimited by default. On a line whose upload is much slower than its download, torrents can use all the upload, leaving other devices and programs on your network with what remains. The help for the upload limit says the same: on a slow uplink, leave headroom for other traffic.

A link profile does not account for a slower upload. The 1 Gbps profile sets the upload limit for a 1000 Mbit/s upload, so on a slower line it limits nothing.


Resolution

1. Set an upload limit below your plan's upload speed. At the top of Quick access, click the Upload figure, type the limit in KiB/s and press Save limits. 1 Mbit/s is about 122 KiB/s, so a 40 Mbit/s upload is about 4880 KiB/s. The limit stays after a restart.
   
   
2. Or let the Performance page propose the limit. Open Performance, select Link under What to test, type the speeds of your plan if you know them, and press Run test. Turn on Advanced at the top of the page. Under Proposed settings, tick Max upload rate (KiB/s, 0 = unlimited). The Headroom left for other traffic slider sets how much of the measured upload stays free, up to 10 %. Press Apply settings (…).
   
   
3. If other traffic still stutters while the torrents run at full speed, lower the limit further. A lower limit leaves more of the upload free.
4. For a short break, press Turtle mode on the Dashboard. It limits upload to 512 KiB/s by default. Press it again to switch it off.

Notice & Advise

• The proposal keeps at least 1 Mbit/s and at most 50 Mbit/s free. On a 40 Mbit/s upload, 2 % is less than 1 Mbit/s, so 1 Mbit/s stays free; at 10 %, 4 Mbit/s.
• The upload limit covers rtorrent only. A backup or a sync job on the NAS that sends to the internet is not limited by it. The hatched band of the Traffic card on the Dashboard shows all traffic on the interface.
• With Night mode set to Lowest upload, downloads go on, uploads run at 1 KB/s during the night.

Ref. links:
Rtorrent 16 guide: Performance tests