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: [email protected] Subject: Re: [c-nsp] Performance issue on link To: [email protected]; [email protected] CC: [email protected] 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/
