Subject: Re: Network latency regressions from 2.6.22 to 2.6.29

From: Eric Dumazet <[email-masked]>
Date: Thu, 16 Apr 2009 21:29:02 +0200

Christoph Lameter a écrit :
> On Thu, 16 Apr 2009, Rick Jones wrote:
> 
>> Does udpping have a concept of service demand a la netperf?  That could help
>> show how much was code bloat vs say some tweak to interrupt coalescing
>> parameters in the NIC/driver.
> 
> No. What does service on demand mean? The ping pong tests are very simple
> back and forths without any streaming or overlay.
> --

Would be good to measure a ping flood, because this one doesnt
need wakeup of a user process on the remote side.

$ ping -f 192.168.20.112 -c 10000
PING 192.168.20.112 (192.168.20.112) 56(84) bytes of data.

--- 192.168.20.112 ping statistics ---
10000 packets transmitted, 10000 received, 0% packet loss, time 3337ms
rtt min/avg/max/mdev = 0.072/0.184/20.011/1.389 ms, pipe 2, ipg/ewma 0.333/0.078 ms

and check if various kernel versions already give you different values (for avg)

When you perform your test, you upgrade kernels of both machines ?