[c-nsp] Performance issue on link

[CiscoNSP List]

Thanks Tony - With multiple sessions (8), I can achieve ~38Mb/sec consistently.

Is it simply not feasible to expect ~40Mb with a single tcp transfer (Without significant adjustments to both Linux servers?)


> Date: Mon, 1 Apr 2013 17:10:42 -0700
> From: td_miles at yahoo.com
> Subject: Re: [c-nsp] Performance issue on link
> To: cisconsp_list at hotmail.com; azher at hep.caltech.edu
> CC: cisco-nsp at puck.nether.net
> 
> Try using multiple TCP sessions  "iperf -P 5"  (note - capital "P").
> 
> 
> regards,
> Tony.
> 
> 
> 
> 
> 
> ----- Original Message -----
> > From: CiscoNSP List <cisconsp_list at hotmail.com>
> > To: Azher Mughal <azher at hep.caltech.edu>
> > Cc: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
> > Sent: Tuesday, 2 April 2013 9:51 AM
> > Subject: Re: [c-nsp] Performance issue on link
> > 
> >T hanks - Ill check them out now
> > 
> >>  Date: Mon, 1 Apr 2013 16:16:36 -0700
> >>  From: azher at hep.caltech.edu
> >>  To: cisconsp_list at hotmail.com
> >>  CC: cisco-nsp at puck.nether.net
> >>  Subject: Re: [c-nsp] Performance issue on link
> >> 
> >>  These might be helpful:
> >> 
> >>  http://fasterdata.es.net/network-tuning/
> >> 
> >> 
> > http://www.mellanox.com/related-docs/prod_software/Performance_Tuning_Guide_for_Mellanox_Network_Adapters.pdf
> >> 
> >>  -Azher
> >> 
> >>  On 4/1/2013 3:51 PM, CiscoNSP List wrote:
> >>  > Hi,
> >>  >
> >>  > We have a 40Mb link between 2 POPs - Latency ~65m/sec (No packet-loss)
> >>  >
> >>  > POP A Is a 7301 and 2960POP B is a 7200 and 4948
> >>  >
> >>  > 40Mb link is connected to the two switches (L2), and then a trunk link 
> > to both routers for all L3.
> >>  >
> >>  > Have a Linux server connected to both switches, and achieve the 
> > following performance:
> >>  >
> >>  > IPERF (UDP)
> >>  > POP A -> POP B - 38.5Mb/secPOP B -> POP A - 38.5Mb/sec
> >>  >
> >>  > IPERF (TCP)
> >>  > POP A -> POP B - ~20Mb/secPOP B -> POP A - ~12Mb/sec
> >>  >
> >>  > FTP
> >>  > POP A -> POP B - ~38Mb/secPOP B -> POP A - ~16Mb/sec
> >>  >
> >>  > WGET
> >>  > POP A -> POP B - ~30Mb/sec POP B -> POP A - ~16Mb/sec
> >>  >
> >>  > Any suggestions on why I am seeing poor performance with TCP 
> > transfers? (Especially POP B -> POP A direction) - I've tried adjusting 
> > the window size in IPERF but it actually made the results worse?
> >>  > Thanks in advance.
> >>  >