transmission bittorrent performance problem

[bozolino]

i have installed transmission via opkg. it runs fine, but the rpc interface (accessed via "transmission remote gui") periodically gets very sluggish, even unaccessible while the cpu goes nuts (see screenshots below). when i look at the torrent data from the command line, the mod dates keep getting updated, so i guess transmission is downloading but chokes on something. the asuswrt-merlin web interface reads very high cpu loads, but htop shows a much more relaxed picture. transmission config is unchanged except the data file paths. the data directory is on a usb 3 stick with decent performance and tested health.

my init-starts in jffs/scripts contains some memory tweaks as suggested by ryzhov_al
echo 524288 > /proc/sys/net/core/rmem_max
echo 524288 > /proc/sys/net/core/wmem_max
echo 8192 > /proc/sys/vm/min_free_kbytes

i'd' appreciate if you could tell me how to get more data on this and/or find possible solutions. thanks in advance!

oh and by the way: coming over from dd-wrt, i really appreciate merlins stable development strategy and the super helpful tone of this forum. kudos to y'all!

TRANSMISSION WORKLOAD

TRANSMISSION ON: CPU+HTOP

TRANSMISSION OFF: CPU+HTOP

 

[bozolino]

bump.

 

[kvic]

i have installed transmission via opkg. it runs fine, but the rpc interface (accessed via "transmission remote gui") periodically gets very sluggish, even unaccessible while the cpu goes nuts (see screenshots below).

I bet everyone using the stock Transmission shall experience such behaviour. I think that's considered 'normal'.

Transmission is a multi-threaded application. There shall be a thread for rpc service. And a pool of worker threads for download/upload.

If you're a developer, worth bump up the priority of the "rpc thread" and reduce the other worker threads a bit. Then recompile. I expect we'll get much snappier user experience.

I'm only an occasional user so I can live with my adjusted expectation. It only happens to me when I'm adding a new torrent (which is a huge download e.g. >1GB).

Alternatively if people have a super fast disk attached to USB3 of the router or a super fast NAS attached to the router, I think the sluggishness is also significantly reduced to an extent not that notable.

 

[bozolino]

thank you for your elaborate comment! router model is RT-AC68U. my torrent download directory is on a usb 3 stick. the stick performs @ 47MB/s write and 82MB/s read when tested with "dd if" from the command line, so it outperforms my 50Mbit downstream/6Mbit upstream internet connection by far. i guess the bottleneck are the threads then rather than raw i/o speed. i wished someone would branch transmission just for a router-adequate recompilation...

 

[kvic]

Also worth limiting number of simultaneous torrents. That can reduce stress on cpu and memory giving better system response overall. In /opt/etc/transmission/settings.json, adjust the queue size:

"download-queue-enabled": true,
"download-queue-size": 3,

3 here limits to max of three torrents that can work at the same time. The rest will be queued up. I find 3 is a sweet spot for my AC56.

 

[Skoven]

I also have the memory tweak by ryzhov_al.
My CPU utilization is also high during torrent downloading trough transmission (2MB/s). It does however drastically decline when the RAM is "cleared" <- i guess writing to the HDD is taxing for the CPU. That's my theory anyway.