[RndTbl] Network performance tuning
kevin.a.mcgregor at gmail.com
Mon Apr 5 21:43:27 CDT 2010
When I choose UDP, I get
0.0-15.0 sec 1.88 MBytes 1.05 Mbits/sec 6.154 ms 0/ 1339 (0%)
No packet loss. 0.1% utilization!
On Mon, Apr 5, 2010 at 8:12 PM, Sean Walberg <swalberg at gmail.com> wrote:
> On a LAN, window sizes aren't going to make that much of a difference.
> First look for the usual suspects - errors on the swich port or NIC.
> If you can grab a copy of the traffic, such as with tcpdump -w test.pcap
> tcp port 5001, you can pull it into wireshark and look for TCP zero window
> conditions, retransmits, and duplicate ACKs. The TCP performance graph will
> also show whether or not the transmission is stalling.
> Is the performance similar using the UDP test? Does it show loss?
> On Mon, Apr 5, 2010 at 7:27 PM, Kevin McGregor <kevin.a.mcgregor at gmail.com
> > wrote:
>> I've been trying to narrow down where my performance bottleneck(s) is
>> (are). I just ran "iperf" from a Windows PC (XP SP3) to my Ubuntu 9.10
>> server. With iperf in "server" mode on the PC, and the client running on the
>> Ubuntu machine, I get
>> 0.0-60.0 sec 4.23 GBytes 606 Mbits/sec
>> Reversed (iperf "server" running on Ubuntu server, client running on the
>> PC), I get
>> 0.0-60.0 sec 1.13 GBytes 162 Mbits/sec
>> Wha...?? Both client and server runs on the PC report TCP window size to
>> be 8 KB, but the Linux client reports 22.4 KB and the Linux server reports
>> 85.3 KB. Increasing that to 256K on both ends has little effect. Does anyone
>> have any suggestions?
>> The Windows NIC is a Realtek RTL8169/8110 Family Gigabit Ethernet; the
>> Ubuntu server is using the Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI
>> Express Gigabit Ethernet controller (rev 01). Time to replace a NIC or two?
>> Roundtable mailing list
>> Roundtable at muug.mb.ca
> Sean Walberg <sean at ertw.com> http://ertw.com/
> Roundtable mailing list
> Roundtable at muug.mb.ca
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