Re: [c-nsp] {Disarmed} Re: IPerf alternative
On 08/12/17 12:55, Saku Ytti wrote: On 12 August 2017 at 18:21, Raymond Burkholder wrote: I have successfully run iperf bidirectionally in tcp as well as udp and hit link limits, even on smaller, lower capacity linux based boxes. On what packet sizes? What link speeds? Linux UDP socket performance Large packet sizes. My goal with that testing has been to perform rough bandwidth testing through provider wan links. It ferrets out basic provider mtu, duplex, and 'noise' issues. is terrible, even with rescvmmsg sendmmsg which iperf does not utilise, the performance is bad. XEON grade server CPU won't congest 1GE single dir - 1.48Mpps, without loss. If you don't care/look at loss, or use low pps, it's different. this is where a/b testing comes in. if test back to back, then I know how the boxes will perform: confirm what their maximum pps rate is, and if there are any kernel based drop or limitations. Then during wan link testing, I can see how things diverge from the baseline. In my particular application, I'm not really testing forwarding performance on any particular box. And as an aid to the original post, I was providing some baseline info, suggesting that iperf, broken as it may be, does provide some acceptable base line performance, depending upon the reason-for-test. If you use TCP you're measuring the host stacks TCP implementation, and you have no visibility on network quality, because packet loss is hidden from you. I agree with that, and do perform udp based testing. iperf has some better post-test statistics when udp testing is performed. But another interesting test scenario, for non-quantitative results, is to run iperf in tcp mode, and run tcpdump at the same time to see if there are more than just acks are happening, and what sort of loss is being corrected. -- Raymond Burkholder https://blog.raymond.burkholder.net/ -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
Re: [c-nsp] {Disarmed} Re: IPerf alternative
On 12 August 2017 at 18:21, Raymond Burkholder wrote: > I have successfully run iperf bidirectionally in tcp as well as udp and hit > link limits, even on smaller, lower capacity linux based boxes. On what packet sizes? What link speeds? Linux UDP socket performance is terrible, even with rescvmmsg sendmmsg which iperf does not utilise, the performance is bad. XEON grade server CPU won't congest 1GE single dir - 1.48Mpps, without loss. If you don't care/look at loss, or use low pps, it's different. If you use TCP you're measuring the host stacks TCP implementation, and you have no visibility on network quality, because packet loss is hidden from you. -- ++ytti ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
Re: [c-nsp] {Disarmed} Re: IPerf alternative
On 08/09/17 06:35, CiscoNSP List wrote: Hi Raymond (Apologies re top post, Hotmail is a pain) - Reliability concerns primarily with bidirectional simultaneous test mode - Single direction test (UDP), we are able to achieve close to a links capacity (1Gb), bidirectional (-r) (Sends one direction first, then the other), also achieves links capacity...but simultaneous bidirectional (-d), we see 50% in both directions (i.e ~450-500Mb) - I dont know if this is a limitation of iperf, but have tried on multiple boxes, back-to-back, and can not get the bidirectional simultaneous test to achieve 1Gb synchronously - Its like IPERF sees the link as only 1Gb, and therefore only sends as a total (500Mb in both directons...Ive also tried multiple threads, but it refuses to go above 50% - If this is a limitation within the software, or theirs another flag I should be using, Id love to hear it :) Have you tried in back to back mode to eliminate network issues? When a test is complete, what do the statistics say? any drops, etc? I have successfully run iperf bidirectionally in tcp as well as udp and hit link limits, even on smaller, lower capacity linux based boxes. As another poster has said, you can run two iperf sessions on each side, one to tx and one to rx. tx1 -> rx2, tx2 -> rx1. You are testing without rate-limiting, firewalls, tunnels, ? -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
