[c-nsp] Performance issue on link

[Blake Dunlap]

As the other guy said, policing is the worst thing you can do. Shape...


On Mon, Apr 1, 2013 at 8:19 PM, Tony <td_miles at yahoo.com> wrote:

> 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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> >
> >
> >
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