Re: Packet time delays on multi-core systems

[Alexey Vlasov]

On Thu, Sep 30, 2010 at 02:44:29PM +0200, Eric Dumazet wrote:
> Le jeudi 30 septembre 2010 ?? 16:23 +0400, Alexey Vlasov a ??crit :
> > On Thu, Sep 30, 2010 at 08:33:52AM +0200, Eric Dumazet wrote:
> > > Le jeudi 30 septembre 2010 ?? 10:24 +0400, Alexey Vlasov a ??crit :
> > > > Here I found some dude with the same problem:
> > > > http://lkml.org/lkml/2010/7/9/340
> >  
> > Well I put interrups from NIC, namely tx/rx query, to different
> > processors and got normal pings by adding LOG rule.
> > 
> > I also found that overruns is constantly growing, I don't know if these are connected.
> > RX packets:2831439546 errors:0 dropped:134726 overruns:947671733 frame:0
> > TX packets:2880849825 errors:0 dropped:0 overruns:0 carrier:0
> > 

Too early to be happy, concerning one rule- the situation got better, but still
there are some time delays. But adding one more rule:
-A INPUT -p all -m state --state INVALID -j LOG --log-prefix
"ipsec:IN-INVALID "
it got totally wrecked:
...
64 bytes from (10.0.2.17): icmp_seq=24 ttl=64 time=0.342 ms
64 bytes from (10.0.2.17): icmp_seq=25 ttl=64 time=1868 ms
64 bytes from (10.0.2.17): icmp_seq=26 ttl=64 time=1448 ms
64 bytes from (10.0.2.17): icmp_seq=27 ttl=64 time=447 ms
64 bytes from (10.0.2.17): icmp_seq=28 ttl=64 time=0.196 ms
...
100 packets transmitted, 100 received, 0% packet loss, time 99990ms
rtt min/avg/max/mdev = 0.108/39.068/1868.663/237.507 ms, pipe 2

# iptables -L -v -n
Chain INPUT (policy ACCEPT 601K packets, 475M bytes)
 pkts bytes target     prot opt in     out     source               destination
  275 11096 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0           state INVALID LOG flags 0 level 4 prefix `ipsec:IN-INVALID '

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 529K packets, 561M bytes)
 pkts bytes target     prot opt in     out     source               destination
13979  839K LOG        tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp dpt:80 flags:0x17/0x02 LOG flags 8 level 4 prefix `ipsec:SYN-OUTPUT-DROP '
 
> > Here goes the typical distribution of interrups on new servers:
> >            CPU0    CPU1    CPU2    CPU3 ... CPU23
> > 752:         11       0       0       0 ...     0 PCI-MSI-edge eth0
> > 753: 2799366721       0       0       0 ...     0 PCI-MSI-edge eth0-rx3
> > 754: 2821840553       0       0       0 ...     0 PCI-MSI-edge eth0-rx2
> > 755: 2786117044       0       0       0 ...     0 PCI-MSI-edge eth0-rx1
> > 756: 2896099336       0       0       0 ...     0 PCI-MSI-edge eth0-rx0
> > 757: 1808404680       0       0       0 ...     0 PCI-MSI-edge eth0-tx3
> > 758: 1797855130       0       0       0 ...     0 PCI-MSI-edge eth0-tx2
> > 759: 1807222032       0       0       0 ...     0 PCI-MSI-edge eth0-tx1
> > 760: 1820309360       0       0       0 ...     0 PCI-MSI-edge eth0-tx0
> > 
> 
> echo 01 >/proc/irq/*/eth0-rx0/../smp_affinity
> echo 02 >/proc/irq/*/eth0-rx1/../smp_affinity
> echo 04 >/proc/irq/*/eth0-rx2/../smp_affinity
> echo 08 >/proc/irq/*/eth0-rx3/../smp_affinity
> 
> 
> cat /proc/irq/*/eth0-rx0/../smp_affinity
> cat /proc/irq/*/eth0-rx1/../smp_affinity
> cat /proc/irq/*/eth0-rx2/../smp_affinity
> cat /proc/irq/*/eth0-rx3/../smp_affinity
 
The last test were made already concerning such rx queue binding:
# cat /proc/irq/60/smp_affinity
001000
# cat /proc/irq/61/smp_affinity
010000
# cat /proc/irq/62/smp_affinity
080000
# cat /proc/irq/63/smp_affinity
800000

Now ksoftirqd eats not only one processor but all oness where I assigned the IRQs.

> > On the old ones:
> >            CPU0       CPU1       CPU2  ...      CPU8
> > 502:  522320256  522384039  522327386  ... 522380267 PCI-MSI-edge eth0
> > 
> 
> What network driver is it (newbox), was it (old box) ?

newbox:
01:00.0 Ethernet controller: Intel Corporation 82575EB Gigabit Network
Connection (rev 02)
driver: igb
version: 1.3.16-k2
firmware-version: 2.1-0
bus-info: 0000:01:00.0

oldbox:
05:00.0 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit
Ethernet Controller (Copper) (rev 01)
driver: e1000e
version: 0.3.3.3-k6
firmware-version: 1.0-0
bus-info: 0000:05:00.0

-- 
BRGDS. Alexey Vlasov.
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