[Click] Packet loss with PollDevice

Yu Chen yuchen at cs.duke.edu
Thu Jan 19 13:59:05 EST 2012


Besides, since the topology is connected by the switches. I checked portstats, 
it shows no drop at the switch.

Also, I tried to increase/decrease the burst size at the poll devices, with 
no luck.
On Thu, Jan 19, 2012 at 01:48:24PM -0500, Yu Chen wrote:
> A correction: User 1 and User 2 are sending to each other, User 3 and User 4
> are sending to each other.
> 
> Besides, I also tried to use one flow, given the default txqueuelen=1000. 
> There are also random losses.
> 
> The Click version is 1.8.0 on Linux 2.6.24.7.
> On Thu, Jan 19, 2012 at 01:45:00PM -0500, Yu Chen wrote:
> > Hi all,
> > 
> > I am having an experiment with the following topology running on Deterlab. I 
> > am having a 4-core Xeon and modified e1000 driver running ore Xeon and modified 
> > e1000 driver running. The memory is 4GB.
> >                      
> > 		     User1
> >                        |
> > 	   User3-----Router------User4		
> >                        |
> > 	             User2
> > 
> > User 1 is sending packet to User 2; User 3 is sending packets to User 4. 
> > The router only routes stuff with best effort. However, what I observed is 
> > very few losses, distributed on a small random set of rounds. What is 
> > surprising is that there are losses on one particular netcard when the sending 
> > rate is only 125,000 packets/second. The loss happens at the receiving phase.
> > 
> > Below is what I have tried:
> > 1' I am using 4 threads, each corresponding to one pair of PollDevice and 
> > ToDevice. 
> > 2' I have changed the queue length at the interface cards. I set txqueuelen=1 
> > for the senders to decrease the possible burstiness. By increasing the 
> > receiving queue length from 64 to 4096
> > (the maximum queue length), the loss rate decreases.
> > 3' I tried to discard the packets on their arrival at the router. In this case, 
> > there is no observed loss.
> > 
> > I am kind of lost at the point. Any suggestions on what can be the possible 
> > reason and what I can try next?
> > 
> > Attached is my code.
> > 
> > Best Regards,
> > Yu 
> > 
> > Router:
> > ----------------------------------------------------------------------- 
> > ddressInfo(router1-w1      10.0.1.1      00:15:17:5d:16:4a,      //eth2
> > user1-w1        10.0.1.2      00:15:17:5d:29:28,      //eth0
> > router1-w2      10.0.2.1      00:15:17:5d:16:48,      //eth0
> > user2-w2        10.0.2.2      00:15:17:57:ce:14,      //eth0
> > router1-w3      10.0.3.1      00:15:17:5d:16:4b,      //eth3
> > user3-w3        10.0.3.2      00:15:17:5d:27:e8,      //eth0
> > router1-w4      10.0.4.1      00:15:17:5d:16:49,      //eth1
> > user4-w4        10.0.4.2      00:15:17:5d:2a:3c,      //eth0
> > );
> > 
> > c1 :: Classifier(12/0806 20/0001,
> >                  12/0806 20/0002,
> >                  12/0800,
> >                  -);
> > c2 :: Classifier(12/0806 20/0001,
> >                  12/0806 20/0002,
> >                  12/0800,
> >                  -);
> > c3 :: Classifier(12/0806 20/0001,
> >                  12/0806 20/0002,
> >                  12/0800,
> >                  -);
> > c4 :: Classifier(12/0806 20/0001,
> >                  12/0806 20/0002,
> >                  12/0800,
> >                  -);
> > 
> > q0 :: Discard;
> > // Idle -> ToDevice(eth1);
> > // Idle -> ToDevice(eth3);
> > // Idle -> ToDevice(eth2);
> > // Idle -> ToDevice(eth0);
> > q1 :: CPUQueue(1000000) -> EtherEncap(0x0800, router1-w1, user1-w1) -> td1 :: ToDevice(eth2);
> > q2 :: CPUQueue(1000000) -> EtherEncap(0x0800, router1-w2, user2-w2) -> td3 :: ToDevice(eth0);
> > q3 :: CPUQueue(1000000) -> EtherEncap(0x0800, router1-w3, user3-w3) -> td2 :: ToDevice(eth3);
> > q4 :: CPUQueue(1000000) -> EtherEncap(0x0800, router1-w4, user4-w4) -> td0 :: ToDevice(eth1);
> > 
> > rt :: LookupIPRouteMP(10.0.1.0/32 0, 10.0.1.1/32 0, 10.0.1.255/32 0,
> >                      10.0.2.0/32 0, 10.0.2.1/32 0, 10.0.2.255/32 0,
> >                      10.0.3.0/32 0, 10.0.3.1/32 0, 10.0.3.255/32 0,
> >                      10.0.4.0/32 0, 10.0.4.1/32 0, 10.0.4.255/32 0,
> >                      10.0.1.0/24 1, 10.0.2.0/24 2, 10.0.3.0/24 3,
> >                      10.0.4.0/24 4, 0.0.0.0/0 0);
> > rt[0] -> Discard;
> > rt[1] -> q1;
> > rt[2] -> q2;
> > rt[3] -> q3;
> > rt[4] -> q4;
> > 
> > pd1 :: PollDevice(eth2) -> c1;
> > c1[0] -> q0;
> > c1[1] -> q0;
> > c1[2] -> DropBroadcasts -> Strip(14) -> GetIPAddress(16) -> rt;
> > c1[3] -> Discard;
> > 
> > pd3 :: PollDevice(eth0) -> c2;
> > c2[0] -> q0;
> > c2[1] -> q0;
> > c2[2] -> DropBroadcasts -> Strip(14) -> GetIPAddress(16) -> rt;
> > c2[3] -> Discard;
> > 
> > pd2 :: PollDevice(eth3) -> c3;
> > c3[0] -> q0;
> > c3[1] -> q0;
> > c3[2] -> DropBroadcasts -> Strip(14) -> GetIPAddress(16) -> rt;
> > c3[3] -> Discard;
> > 
> > pd0 :: PollDevice(eth1) -> c4;
> > c4[0] -> q0;
> > c4[1] -> q0;
> > c4[2] -> DropBroadcasts -> Strip(14) -> GetIPAddress(16) -> rt;
> > c4[3] -> Discard;
> > 
> > StaticThreadSched(pd2 0, td0 0, pd0 1, td2 1, pd3 2, td1 2, pd1 3, td3 3);
> > 
> > User:
> > //
> > AddressInfo(router1-w1      10.0.1.1      00:15:17:5d:16:4a,      //eth2
> > user1-w1        10.0.1.2      00:15:17:5d:29:28,      //eth0
> > router1-w2      10.0.2.1      00:15:17:5d:16:48,      //eth0
> > user2-w2        10.0.2.2      00:15:17:57:ce:14,      //eth0
> > router1-w3      10.0.3.1      00:15:17:5d:16:4b,      //eth3
> > user3-w3        10.0.3.2      00:15:17:5d:27:e8,      //eth0
> > router1-w4      10.0.4.1      00:15:17:5d:16:49,      //eth1
> > user4-w4        10.0.4.2      00:15:17:5d:2a:3c,      //eth0
> > );
> > //Send
> > udp :: FastUDPSource(RATE 400000, LIMIT 20000000, LENGTH 78,
> > 		     SRCETH user1-w1, SRCIP user1-w1, SPORT 1,
> > 		     DSTETH router1-w1, DSTIP user2-w2, DPORT 1,
> > 		     CHECKSUM false, INTERVAL 0, ACTIVE false)
> > 	-> ToDevice(eth0);
> > 
> > s :: Script(TYPE ACTIVE, write ctr.reset, write udp.active false, 
> > 	    wait 1, wait 9, write udp.active true);
> > 
> > 
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