On Mon, 2010-09-13 at 15:28 +0200, przemolicc@poczta.fm wrote:

Hello,

we have one application which gets some data from our database but to print just one result it connects many times to the database over WAN. Of course there are some performance related problems with this type of work. I'd like to analyze (not necessary online) its tcp flow especially its latency (using port redirect on switch). Do you know any software (similar to tcpdump or so) which will let me graph/paint latency between each connection and each tcp flow ?

Regards Przemek

--- I say talk to your DB Admin | Hit the Db once and not many times (connection), there's your problem at least one.

Latency starts at the Application Layer then on down the Hardware then the Network. You can throw a lot of money away also on it. There are kernel options for networking latency (see the kernel pages docs). Although you want improve it hardly any with the mainline kernel. The WIRE is the Killer and App priority.

To start with you are going over a link you have NO control of so your really stuck unless you have DEEP Pockets.

Any way one of the best tools to use is Netperf [1]. You can build your own rpm from the gz package.

What's the latency now???

John

[1]. http://www.netperf.org/netperf/ a loopback netperf -c TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to foomahine (127.0.0.1) port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % U us/KB us/KB

87380 16384 16384 10.00 3002.26 100.00 -1.00 2.729 -1.000