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echo: nthelp
to: Gregg N
from: Rich
date: 2005-05-19 23:40:28
subject: Re: Crappy Windows 2000/XP UDP performance

From: "Rich" 

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   No.  I haven't had time to see if there is a difference depending on =
whether or not the firewall is enabled or if I use IPv6 instead of IPv4. =
 There could be other factors but those are the two that if I had time I =
could try easily.

Rich

  "Gregg N"  wrote in message =
news:428b7482$1{at}w3.nls.net...
  Any idea what's causing this? Someone else said he got better results =
using a non-blocking socket but I did not look at what he did or verify =
his results.

  Gregg
    "Rich"  wrote in message news:428abf18{at}w3.nls.net...
       I tried one of my own tools.  With a UDP payload size of 1K I can =
get 50% network utilization of a 1GB adapter with 100% CPU utilization.  =
If I increase the payload size to 1025 bytes then I get 4% network =
utilization with around 35% CPU utilization.

    Rich

      "Gregg N"  wrote in message =
news:428a3454{at}w3.nls.net...
      We have an application that sends UDP datagrams over gigabit =
ethernet. It=20
      was not achieving the performance we expected, so we ran some =
tests. When=20
      the packet size is 1024 bytes or less, we can send 40,000 packets =
per=20
      second, or about 312.5 Mbps. Not great, but acceptable. However, =
with packet=20
      sizes greater than 1024 bytes, we could not send more than about =
3700=20
      packets per second, or about 28.9 Mbps (note this is on a 1Gb =
interface!).=20
      The process is not CPU bound, so that is not what is causing the =
limitation.

      We verified this using the iperf tool from this location:

      http://www.noc.ucf.edu/Tools/Iperf/default.htm

      which you can try yourself. Use the command

      iperf -u -l 1024 -c dummytarget -i 1 -b 500m -w 256k

      and see what it shows with -l 1024 and -l 1025. You can substitute =
a smaller=20
      value for -b (bandwidth) on a 100 Mb interface.

      Apparently, this has been encountered by others. For example, see

      =
http://groups.google.co.uk/group/comp.protocols.tcp-ip/browse_frm/thread/=
7ec2673b5471490f/409197bb36320ace?hl=3Den&lr=3D&ie=3DUTF-8&oe=
=3DUTF-8&safe=3Doff&rnum=3D1&prev=3D/groups%3Fhl%3Den%26lr%3D=
%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%26selm%3D2003-01-27-01-42.0%2540c=
hch.demon.co.uk#409197bb36320ace

      and

      =
http://groups.google.co.uk/group/alt.winsock.programming/browse_frm/threa=
d/f05890d2b6b71452/8d8873987d71893b?tvc=3D1&q=3Dalanjmcf+1024&hl=3D=
en#8d8873987d71893b

      and

      http://www.chch.demon.co.uk/wintest/wintest.html

      However, I could not find anything about this on the MS web site. =
Does=20
      anyone have any idea what is causing this?

      Thanks.

      Gregg

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No.  I haven't had =
time to see if=20
there is a difference depending on whether or not the firewall is = enabled or if=20
I use IPv6 instead of IPv4.  There could be other factors but
those = are the=20
two that if I had time I could try easily.
 
Rich
 
"Gregg N" <invalid{at}invalid.invalid>">mailto:invalid{at}invalid.invalid">invalid{at}invalid.invalid> = wrote in=20 message news:428b7482$1{at}w3.nls.net... Any idea what's causing this? Someone else said he = got=20 better results using a non-blocking socket but I did not look at what = he did=20 or verify his results. Gregg
"Rich" <{at}> wrote in message news:428abf18{at}w3.nls.net... I tried one of my own = tools. =20 With a UDP payload size of 1K I can get 50% network utilization of a = 1GB=20 adapter with 100% CPU utilization. If I increase the payload = size to=20 1025 bytes then I get 4% network utilization with around 35% CPU=20 utilization. Rich "Gregg N" <invalid{at}invalid.invalid>=20">mailto:invalid{at}invalid.invalid">invalid{at}invalid.invalid>=20 wrote in message news:428a3454{at}w3.nls.net...We= =20 have an application that sends UDP datagrams over gigabit = ethernet. It=20 was not achieving the performance we expected, so we ran some = tests.=20 When the packet size is 1024 bytes or less, we can send 40,000 = packets=20 per second, or about 312.5 Mbps. Not great, but acceptable. = However,=20 with packet sizes greater than 1024 bytes, we could not send = more than=20 about 3700 packets per second, or about 28.9 Mbps (note this = is on a=20 1Gb interface!). The process is not CPU bound, so that is not = what is=20 causing the limitation.We verified this using the iperf = tool from=20 this location:http://www.noc.uc" target="new">http://www.noc.uc=">http://www.noc.ucf.edu/Tools/Iperf/default.htm">http://www.noc.uc= f.edu/Tools/Iperf/default.htmwhich=20 you can try yourself. Use the commandiperf -u -l 1024 -c=20 dummytarget -i 1 -b 500m -w 256kand see what it shows with = -l 1024=20 and -l 1025. You can substitute a smaller value for -b = (bandwidth) on=20 a 100 Mb interface.Apparently, this has been encountered = by=20 others. For example, seehttp://groups.google.co.uk/group/comp.protocols.tcp-ip/browse_frm= /thread/7ec2673b5471490f/409197bb36320ace?hl=3Den&amp;lr=3D&amp;i= e=3DUTF-8&amp;oe=3DUTF-8&amp;safe=3Doff&amp;rnum=3D1&amp;= prev=3D/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%2= 6selm%3D2003-01-27-01-42.0%2540chch.demon.co.uk#409197bb36320ace">http://= groups.google.co.uk/group/comp.protocols.tcp-ip/browse_frm/thread/7ec2673= b5471490f/409197bb36320ace?hl=3Den&amp;lr=3D&amp;ie=3DUTF-8&a= mp;oe=3DUTF-8&amp;safe=3Doff&amp;rnum=3D1&amp;prev=3D/groups%= 3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%26selm%3D2003-01= -27-01-42.0%2540chch.demon.co.uk#409197bb36320aceand<= A=20 = href=3D"http://groups.google.co.uk/group/alt.winsock.programming/browse_f= rm/thread/f05890d2b6b71452/8d8873987d71893b?tvc=3D1&amp;q=3Dalanjmcf+= 1024&amp;hl=3Den#8d8873987d71893b">http://groups.google.co.uk/group/a= lt.winsock.programming/browse_frm/thread/f05890d2b6b71452/8d8873987d71893= b?tvc=3D1&amp;q=3Dalanjmcf+1024&amp;hl=3Den#8d8873987d71893b<= BR>andhttp://www.chch" target="new">http://www.chch=">http://www.chch.demon.co.uk/wintest/wintest.html">http://www.chch= .demon.co.uk/wintest/wintest.htmlHowever,=20 I could not find anything about this on the MS web site. Does = anyone=20 have any idea what is causing=20 = this?Thanks.Gregg ------=_NextPart_000_010A_01C55CCC.234D27F0-- --- BBBS/NT v4.01 Flag-5
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