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 <[email protected]> >To: "[email protected]" <[email protected]>; Azher Mughal ><[email protected]> >Cc: "[email protected]" <[email protected]> >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: [email protected] >> To: [email protected]; [email protected] >> Date: Tue, 2 Apr 2013 11:28:50 +1100 >> CC: [email protected] >> 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: [email protected] >> > Subject: Re: [c-nsp] Performance issue on link >> > To: [email protected]; [email protected] >> > CC: [email protected] >> > >> > Try using multiple TCP sessions "iperf -P 5" (note - capital "P"). >> > >> > >> > regards, >> > Tony. >> > >> > >> > >> > >> > >> > ----- Original Message ----- >> > > From: CiscoNSP List <[email protected]> >> > > To: Azher Mughal <[email protected]> >> > > Cc: "[email protected]" <[email protected]> >> > > 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: [email protected] >> > >> To: [email protected] >> > >> CC: [email protected] >> > >> 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. >> > >> > >> >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ > > > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
