[Cerowrt-users] SQM Setup and Performance

[Jeremy Tourville]

Hello, I followed your excellent instructions here -
http://www.bufferbloat.net/projects/cerowrt/wiki/Setting_up_SQM_for_CeroWrt_310
 
I am using build 3.10.24-8
 
I am using a DSL line rated at 6 Mbps down and 512kbps up.  My real throughput without SQM enabled is 5.7Mbps down and 450kbps up.
After enabling SQM my throughput has dropped to approximately 4.5Mbps down and 350 kbps up.  Does this seem like an amount that is expected? (within norms?)
It would seem reasonable that I should expect some performance loss at the expense of better bufferbloat management based on setting 85-95% of actual download/upload speeds.  Please correct me if I am wrong. :-)  But my question is, how much is too much?  The setting of SQM does fix the bufferbloat issue as evidenced by ping testing and times for packets.  With SQM on all packets were 100ms or less.  With SQM off the times jumped to over 500ms or more during the speed testing. 
 
For reference I have set the parameters as indicated in the screenshots.  I have changed only two variables and tested after each change as indicated in the grid below.
 


 
 
 
 
 
  
  Que setup script
  Per packet
  overhead
  test
  results
 
 
  Test #1
  simple.qos
  40
  no buffer, less
  throughput
  <100ms, 4.5mbps
  down
 
 
  Test #2 
  simple.qos
  44
  no buffer, less
  throughput
  <100ms, 4.5mbps
  down
 
 
  Test #3
  simplest.qos
  40
  no buffer, less
  throughput
  <100ms, 4.5mbps
  down
 
 
  Test #4
  simplest.qos
  44
  no buffer, less
  throughput
  <100ms, 4.5mbps
  down

 

 
I also read your statement- 
>>>"The CeroWrt development team has been working to nail down a no-brainer set of instructions for eliminating bufferbloat - the lag/latency that kills voice & video chat, gaming, and overall network responsiveness. The hard part is that optimal configuration of the Smart Queue Management (SQM) link is difficult - there are tons of options an ISP can set. Although CeroWrt can adapt to any of them, it's difficult to find out the exact characteristics of the link you have."
 
What info do I need to get from my ISP to best optimize my connection?
 
I also recognize that this could be an issue that requires multiple changes at once.  I am curious to know from the experts what your thoughts are on this.  Many thanks in advance!
 
-Jeremy
 		 	   		  
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