[c-nsp] Performance issue on link

[CiscoNSP List]

Hi Tony - Link is new, no duplex issues (On our side, nor reported by carrier)

No traffic on the link.

udp test (both directions) looks fine (Hopefully formatting isnt screwed up - but achieve ~38.5Mb/sec both directions):


[ ID] Interval       Transfer     Bandwidth
[  5]  0.0-10.0 sec  47.7 MBytes  40.0 Mbits/sec
[  5] Sent 34015 datagrams
[  3]  0.0-10.0 sec  46.0 MBytes  38.6 Mbits/sec  0.040 ms 1180/34014 (3.5%)
[  3]  0.0-10.0 sec  1 datagrams received out-of-order
[  5] Server Report:
[  5]  0.0-10.0 sec  46.0 MBytes  38.5 Mbits/sec  0.051 ms 1233/34014 (3.6%)
[  5]  0.0-10.0 sec  1 datagrams received out-of-order


The 2 linux servers are on separate L3 subnets (Connected to the local router in each POP) - I can potentially trunk a new vlan between the 2 POPs and have them connected without touching the routers...UDP tests are looking good though, so if it was an issue with the router(s), wouldn't I see problems with UDP also?

Thanks again for your assistance, much appreciated.


Date: Mon, 1 Apr 2013 18:19:40 -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

That doesn't sound at all good. No way should you need that many (25) sessions.

Is there any other traffic on the link ? Is it brand new ? Any duplex mismatch type issues ?

I would suggest running an "iperf -u -d" to run UDP in both directions at the same time, might turn up something unusual. Remove any other devices (ie. your routers) before testing so you will know that is not a problem. I assume your two linux test machines are on the same L3 subnet from what you've described ?


regards,
Tony.




        From: CiscoNSP List <cisconsp_list at hotmail.com>
 To: "td_miles at yahoo.com" <td_miles at yahoo.com>; 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 10:37 AM
 Subject: RE: [c-nsp] Performance issue on link
   



Sorry - Forgot to add:

POP A -> POP B - only requires 8 sessions, but POP B -> POP A requires 25 sessions to achieve ~38Mb?



> From: cisconsp_list at hotmail.com
> To: td_miles at yahoo.com; azher at hep.caltech.edu
> Date: Tue, 2 Apr 2013 11:28:50 +1100
> CC: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Performance issue on link
> 
> 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.
> > >>  >
>  		 	   		  
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