Useful speed limits

Got a good idea? Want to share it? Then please take a moment to submit it.
Post Reply
Erik Sperling Johansen
Posts: 10
Joined: Wed Jan 13, 2016 1:22 pm

Useful speed limits

Post by Erik Sperling Johansen » Fri Jan 15, 2016 11:29 am

Speed limits are currently not very functional. 
 
1) It should not be necessary to stop and start connections in order to apply a new speed limit. 
2) The "per-connection" term in the favorite's speed limit is unclear. Does this mean
  a) Per TCP Connection
  b) Per active Worker (that is, total speed limit for all segmented download connections)
  c) Per site
3) Speed limits seem to work for a while, and then they apparently disappear. If I restart the SmartFTP client, they start to be applied again
4) The actual download speed is limited in a way that allows it to fluctuate above the set limit. Effective speed with a 1000 kB/sec limit varies between 0.98 and 1.05 MB/sec. It would be good if a speed limit meant that SmartFTP read at most exactly the requested amount off sockets per second, and rather kept larger socket receive buffers.
 
The intent with speed limiting typically is to free up bandwidth on a saturated link, because the link is needed for other work. This isn't working now.
 
Optimally, I'd like to keep the current "limit global bandwidth" settings, but add an Enabled/Disabled toggle that is accessible directly in the UI. 
 
 
 

mb
Posts: 12029
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Useful speed limits

Post by mb » Wed Jan 20, 2016 4:46 pm

>3) Speed limits seem to work for a while, and then they apparently disappear. If I restart the SmartFTP client, they start to be applied again
Can you provide instructions on how to reproduce this issue? Preferably with the least complex transfer setup as possible.
Last edited by mb on Wed Jan 20, 2016 4:46 pm, edited 1 time in total.

Erik Sperling Johansen
Posts: 10
Joined: Wed Jan 13, 2016 1:22 pm

Re: Useful speed limits

Post by Erik Sperling Johansen » Sat Jan 23, 2016 4:33 am

There's no clear instructions, this seems to happen for every transfer here. When I start transfer of a backup set from a server in Germany, the speed limit will be adhered to anywhere from 2 minutes to a few hours, but it will always stop working and SmartFTP will start maximizing my line.
* I've enabled speed limits for every part of the week, and turn it on/off by setting a limit or 0
* I stop and restart transfers to get the limits applied. When this does not appear to work, I exit and restart the client.
* I connect to a single server
* I use TLS, all connections private
* I use segmented downloads, 10 parts, size threshold 20480 KB
* I vary between 1-3 workers
* Transferred file sized vary from a few kB to 5-6GB each.
Where I'm currently living, international connections are slow and unreliable. It's not uncommon having a tcp connection slowed to a crawl (5-6kB/sec), then after terminating the connection and reestablishing it, speed goes back to normal. Normal varies with time of day, a single TCP connection could be at around 50 kB/sec or it could be 1MB/sec. Connections regularly are reset or slowed to an effective 0B/sec data rate(this sometimes seems to make SmartFTP stuck as it doesn't discard connections with no actual data rate).
Side note: Every now and then, but seemingly unrelated to whether speed limits work or not, the total transfer speed displayed at the bottom of the transfer queue is 0, regardless of how fast the above workers claim to transfer.
Can you clarify 2) in my original question?

mb
Posts: 12029
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Useful speed limits

Post by mb » Sat Jan 23, 2016 10:05 am

Do you only change the Global Speed Limits in the Settings - Transfer dialog? Or do you also set per connection speed limits?
What do you set the Upload and Download Speed to?
 
Speed limits generally do not work reliably if you do not have at least a bandwidth of 2 MBit/s.
Last edited by mb on Sat Jan 23, 2016 10:06 am, edited 1 time in total.

Erik Sperling Johansen
Posts: 10
Joined: Wed Jan 13, 2016 1:22 pm

Re: Useful speed limits

Post by Erik Sperling Johansen » Sun Jan 24, 2016 10:01 am

I only change global limits. See 2) in my original post - I do not know what the per-connection speed limit means. Could you please clarify this?
 
Some additional info:
 
* When the speed limit stops working, stopping and then starting the transfer does not help. Speed limit is still ignored.
* Same problem when data transfers are not encrypted
* Restarting SmartFTP causes the speed limit to be applied again
* Changing the global speed limit, even without stopping and restarting transfers, causes it to start being limited again.

mb
Posts: 12029
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Useful speed limits

Post by mb » Sun Jan 24, 2016 2:22 pm

>2
Per TCP connection.
 
We have found a bug in the calculation. We will release the fix in the next build.
Last edited by mb on Sun Jan 24, 2016 2:43 pm, edited 1 time in total.

mb
Posts: 12029
Joined: Thu Oct 11, 2001 1:24 pm
Display name: Mat (SmartFTP)
Contact:

Re: Useful speed limits

Post by mb » Tue Jan 26, 2016 6:11 pm

The new build is available now:
https://www.smartftp.com/download
 
Could you let us know whether it solves the issue you were seeing?

Erik Sperling Johansen
Posts: 10
Joined: Wed Jan 13, 2016 1:22 pm

Re: Useful speed limits

Post by Erik Sperling Johansen » Wed May 25, 2016 1:32 am

Speed limits seems to work better now.

Post Reply