[Libtorrent-devel] performance

[Alexey Polyakov]

Jerker Nyberg wrote:
> What do I tweek to get the best seeding performance out of rtorrent? I 
> have 1 Gbit/s bandwidth to play with, six machines with 2 drives and 2 
> GByte RAM each. I copied the data (100 GB) to all 12 drives and got 
> around 300 Mbit/s total upload bandwidth. I used a rtorrent process 
> for each drive. (I seeded some free OSes.)

> It seems like the drives are busy seeking. The bandwidth for each 
> drive is only 3 MByte/s... How can I improve this? Any knobs to turn?

What OS (kernel version) and filesystem type do you have? How many 
upload connections per server do you have in rtorrent?

> I would like rtorrent to really read every chunk into the disk cache 
> the first time it is accessed. I know rtorrent is using mmap'ed read 
> ahead using madvise. Shouldn't a whole chunk be read into RAM the 
> first time it is accessed? Or is this what is done? Are the chunks not 
> big enough? Chunk sizes are 262144, 524288 or 1048576 bytes. Any other 
> ideas?

I think that would hurt performance as 2GB is not enough to hold all 
transferring chunks at 200 mbit/sec.