Issues with High Latency on PPPOE Reconnect
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Anybody has another Idea what might be going on here? Why is the em0 and em1 que taking that much CPU?
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I wonder if it's some interrupt issue. Try checking
vmstat -iIs there some huge interrupt rate on the em intertupts? Can you see if it spikes at a reconnect?
Also check the interrupt graph in System > Monitoring.If there is something there you might be able to tweak the interrupt moderation settings for em.
Steve
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During a reconnect I ran the vmstat -i command a few times, this is what I've got:
#vmstat -i interrupt total rate irq4: uart0 4 0 irq16: ehci0 1819312 1 irq23: ehci1 2425630 2 cpu0:timer 1301077192 1073 cpu1:timer 42493717 35 cpu3:timer 57991184 48 cpu2:timer 599667271 494 irq264: em0 2223977382 1834 irq265: em1 1785916192 1472 irq266: em2 2958347521 2439 irq267: hdac0 7114 0 irq268: re0 181548785 150 irq269: ahci0 3925301 3 Total 9159196605 7551 # vmstat -i interrupt total rate irq4: uart0 4 0 irq16: ehci0 1819312 1 irq23: ehci1 2425630 2 cpu0:timer 1301080827 1073 cpu1:timer 42497352 35 cpu3:timer 57994819 48 cpu2:timer 599670906 494 irq264: em0 2223977433 1834 irq265: em1 1785916305 1472 irq266: em2 2958347577 2439 irq267: hdac0 7114 0 irq268: re0 181548785 150 irq269: ahci0 3925307 3 Total 9159211371 7551 # vmstat -i interrupt total rate irq4: uart0 4 0 irq16: ehci0 1819318 1 irq23: ehci1 2425638 2 cpu0:timer 1301083170 1073 cpu1:timer 42499612 35 cpu3:timer 57997160 48 cpu2:timer 599673173 494 irq264: em0 2223983068 1834 irq265: em1 1785920972 1472 irq266: em2 2958353105 2439 irq267: hdac0 7114 0 irq268: re0 181548785 150 irq269: ahci0 3925316 3 Total 9159236435 7551 # interrupt total rate irq4: uart0 4 0 irq16: ehci0 1819324 1 irq23: ehci1 2425646 2 cpu0:timer 1301087566 1073 cpu1:timer 42503812 35 cpu3:timer 58001340 48 cpu2:timer 599677486 494 irq264: em0 2223989223 1834 irq265: em1 1785927209 1472 irq266: em2 2958360786 2439 irq267: hdac0 7114 0 irq268: re0 181548785 150 irq269: ahci0 3925330 3 Total 9159273625 7551There was a spike that caused the vmstat -i command to hang, so if there was something that should have been captured.
Looking at the graph, set at the shortest (1 minute) interval, interrupt is at 15%, system at 50% and user at 15% at the minute with the reconnect. Afterwards everything goes back to normal again (System at 4%, everything else less than 0.5%).
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Anyone has another idea? I really have no clue what else to try or how to debug. It all should work, but it doesn't. How could I try to track down the issue?
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I notice you have that high CPU usage in state
*if_lawhich I assume is truncated from if_lagg.What sort of lagg is that? What interfaces are in it?
Can you remove the lagg entirely and put the VLANs over one interface directly as a test?
It's weird though. I have a setup at home that's almost exactly like that. PPPoE connections on VLANs on an LACP LAGG.
Steve
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It is an LACP lagg with all interfaces in it (3 Intels and 1 Realtek), as I've mentioned before I've tried removing the Realtek from it before but no difference.
I'll try adding them to the interface directly tomorrow, I'll have to find a time where downtime doesn't matter.
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I think I found the issue: It was something with the tuneables. It could have been the ip redirect thingy, but I've changed a few more before this reboot. Anyways, this is how it looks like know during a PPPoE reconnect (only lines with more than 1ms response time are shown, interval is 0.05ms):
64 bytes from 192.168.1.1: icmp_seq=4223 ttl=64 time=79.2 ms 64 bytes from 192.168.1.1: icmp_seq=4224 ttl=64 time=23.2 ms 64 bytes from 192.168.1.1: icmp_seq=4225 ttl=64 time=126 ms 64 bytes from 192.168.1.1: icmp_seq=4226 ttl=64 time=72.8 ms 64 bytes from 192.168.1.1: icmp_seq=4227 ttl=64 time=16.8 ms 64 bytes from 192.168.1.1: icmp_seq=4236 ttl=64 time=1.10 ms 64 bytes from 192.168.1.1: icmp_seq=4255 ttl=64 time=65.5 ms 64 bytes from 192.168.1.1: icmp_seq=4256 ttl=64 time=9.53 ms 64 bytes from 192.168.1.1: icmp_seq=4257 ttl=64 time=121 ms 64 bytes from 192.168.1.1: icmp_seq=4258 ttl=64 time=67.8 ms 64 bytes from 192.168.1.1: icmp_seq=4259 ttl=64 time=12.3 ms 64 bytes from 192.168.1.1: icmp_seq=4278 ttl=64 time=1.10 ms 64 bytes from 192.168.1.1: icmp_seq=4363 ttl=64 time=2.16 ms 64 bytes from 192.168.1.1: icmp_seq=4461 ttl=64 time=63.3 ms 64 bytes from 192.168.1.1: icmp_seq=4462 ttl=64 time=7.35 ms 64 bytes from 192.168.1.1: icmp_seq=4463 ttl=64 time=114 ms 64 bytes from 192.168.1.1: icmp_seq=4464 ttl=64 time=60.7 ms 64 bytes from 192.168.1.1: icmp_seq=4465 ttl=64 time=4.71 ms 64 bytes from 192.168.1.1: icmp_seq=4496 ttl=64 time=79.2 ms 64 bytes from 192.168.1.1: icmp_seq=4497 ttl=64 time=23.2 ms 64 bytes from 192.168.1.1: icmp_seq=4498 ttl=64 time=125 ms 64 bytes from 192.168.1.1: icmp_seq=4499 ttl=64 time=68.1 ms 64 bytes from 192.168.1.1: icmp_seq=4500 ttl=64 time=12.1 ms 64 bytes from 192.168.1.1: icmp_seq=4514 ttl=64 time=103 ms 64 bytes from 192.168.1.1: icmp_seq=4515 ttl=64 time=47.6 ms 64 bytes from 192.168.1.1: icmp_seq=4517 ttl=64 time=104 ms 64 bytes from 192.168.1.1: icmp_seq=4518 ttl=64 time=48.7 msThis should be okay, right? Or is there more room for improvement?
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Actually that did not solve the issue..... I rebooted pfsense, added the Intel NIC I removed from the LACP earlier back to the bridge and it behaved just like it used to.
Now I have removed em2 from the LAGG again and unplugged it, and I am getting those good times again and also the radvd problem is solved. Now of course I want to figure out the real source of this problem: The card causing the issues is em2,
pciconf -lvsays:em2@pci0:0:25:0: class=0x020000 card=0x1494103c chip=0x15028086 rev=0x04 hdr=0x00 vendor = 'Intel Corporation' device = '82579LM Gigabit Network Connection (Lewisville)' class = network subclass = ethernetAnybody has any idea why this card is causing such massive problems in my setup?
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So you still have the other em NICX and the re NIC in that lagg when the ping latency looks good?
Or is that with the lagg effectively removed?Steve
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Yes I still have the LACP containing the other 2 em NICs and the re NIC, just em2 is now no longer connected to the LACP and i've pulled out the Ethernet cable aswell.
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Curious. You could try enabling lacp debugging.
sysctl net.link.lagg.lacp.debug=1Are those em NICs all the same type?
Steve
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No they are not all the same, em2 is a different one (it's the onboard NIC). The other ones are 82571EB.
Now that I know what causes the issue I will check if I still have one of those computers somewhere. I need a machine for testing all the stuff.
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Could this patch solve the issue? https://svnweb.freebsd.org/base?view=revision&revision=336313
Looks like there are known Problems with that chipset causing some hangs, looks like exactly what I've experienced.
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TSO should be disabled by default in pfSense anyway in System > Advanced > Networking. But check the ifconfig output for the parent NICs to be sure.
Steve
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I have it enabled, is it possible that thats what caused all the issues? I assumed that for Intel NICs that works fine. Do I understand it correctly that the patch is basically disabling the TSO, so there's no point in having it enabled on my installation?
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It does appear to. I would definitely try that.
Steve
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Unfortunately i can't post the ifconfig output as that constantly triggers the spam filter. On em2 there's nothing about tso, on em0 and em1 theres tso4. Also em2 is still unplugged, not sure if that matters.
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It may be correctly disabled on the NIC but passed through when it's added to the lagg group. Does lagg0 show TSO4?
Steve
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I have tried globally disabling TSO, but that did not solve the issue. After a reboot the issue was back, pulling the cable did not help, only removing the interface from the LAGG.
As this seems to be an issue with the specific Intel NIC, maybe someone can get one of these and look into the issue.
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Are you seeing entries in the ppp log that look like this?:
Nov 21 16:46:35 pfsense ppp: [opt4_link0] Link: reconnection attempt 24 Nov 21 16:46:35 pfsense ppp: [opt4_link0] PPPoE: can't connect "[26]:"->"mpd98452-0" and "[17e]:"->"left": No such file or directory Nov 21 16:46:35 pfsense ppp: [opt4_link0] can't remove hook mpd98452-0 from node "[26]:": No such file or directory Nov 21 16:46:35 pfsense ppp: [opt4_link0] Link: DOWN event Nov 21 16:46:35 pfsense ppp: [opt4_link0] LCP: Down event Nov 21 16:46:35 pfsense ppp: [opt4_link0] Link: reconnection attempt 25 in 4 seconds Nov 21 16:46:35 pfsense ppp: [wan_link0] Link: reconnection attempt 33 Nov 21 16:46:35 pfsense ppp: [wan_link0] PPPoE: can't connect "[1b]:"->"mpd17126-0" and "[4e]:"->"left": No such file or directory Nov 21 16:46:35 pfsense ppp: [wan_link0] can't remove hook mpd17126-0 from node "[1b]:": No such file or directory Nov 21 16:46:35 pfsense ppp: [wan_link0] Link: DOWN event Nov 21 16:46:35 pfsense ppp: [wan_link0] LCP: Down event Nov 21 16:46:35 pfsense ppp: [wan_link0] Link: reconnection attempt 34 in 2 secondsAnd entries in the System log like this:
Nov 21 16:45:17 pfsense kernel: vlan0: changing name to 'lagg0.101' Nov 21 16:45:21 pfsense kernel: vlan1: changing name to 'lagg0.102' Nov 21 16:45:21 pfsense kernel: vlan2: changing name to 'lagg0.103'There are a number of open bugs that seem likely to be related if so. Specifically:
https://redmine.pfsense.org/issues/9148Steve
