Date: Wed, 5 Aug 2009 00:30:20 -0700 (PDT) From: alexpalias-bsdstable@yahoo.com To: freebsd-stable@freebsd.org Subject: em driver input errors Message-ID: <27085.65527.qm@web56408.mail.re3.yahoo.com>
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Good day
I'm looking for suggestions for tuning my setup in order to get rid of the input errors I'm seeing on em0, em1 and em2 when using vlans.
[This message (excluding the description of the second machine at the end) has also been sent to the freebsd-net mailing list, a few days ago]
I'm running a FreeBSD 7.2 router and I am seeing a lot of input errors on one of the em interfaces (em0), coupled with (at approximately the same times) much fewer errors on em1 and em2. Monitoring is done with SNMP from another machine, and the CPU load as reported via SNMP is mostly below 30%, with a couple of spikes up to 35%.
Software description:
- FreeBSD 7.2-RELEASE-p2, amd64
- bsnmpd with modules: hostres and (from ports) snmp_ucd
- quagga 0.99.12 (running only zebra and bgpd)
- netgraph (ng_ether and ng_netflow)
Hardware description:
- Dell machine, dual Xeon 3.20 GHz, 4 GB RAM
- 2 x built-in gigabit interfaces (em0, em1)
- 1 x dual-port gigabit interface, PCI-X (em2, em3) [see pciconf near the end]
The machine receives the global routing table ("netstat -nr | wc -l" gives 289115 currently).
All of the em interfaces are just configured "up", with various vlan interfaces on them. Note that I use "kpps" to mean "thousands of packets per second", sorry if that's the wrong shorthand.
- em0 sees a traffic of 10...22 kpps in, and 15...35 kpps out. In bits, it's 30...120Mbits/s in, and 100...210Mbits/s out. Vlans configured are vlan100 and vlan200, and most of the traffic is on vlan100 (vlan200 sees 4kpps in / 0.5kpps out maximum, with the average at about one third of this). em0 is the external interface, and its traffic corresponds to the sum of traffic through em1 and em2
- em1 has 5 vlans, and sees about 22kpps in / 11kpps out (maximum)
- em2 has a single VLAN, and sees about 4...13kpps both in and out (almost equal in/out during most of the day)
- em3 is a backup interface, with 2 VLANS, and is the only one which has seen no errors.
Only the vlans on em0 are analyzed by ng_netflow, and the errors I'm seeing have started appearing days before netgraph was even loaded in the kernel.
Tuning done:
/boot/loader.conf:
hw.em.rxd=4096
hw.em.txd=4096
Witout the above we were seeing way more errors, now they are reduced, but still come in bursts of over 1000 errors on em0.
/etc/sysctl.conf:
net.inet.ip.fastforwarding=1
dev.em.0.rx_processing_limit=300
dev.em.1.rx_processing_limit=300
dev.em.2.rx_processing_limit=300
dev.em.3.rx_processing_limit=300
Still seeing errros, after some searching the mailing lists we also added:
# the four lines below are repeated for em1, em2, em3
dev.em.0.rx_int_delay=0
dev.em.0.rx_abs_int_delay=0
dev.em.0.tx_int_delay=0
dev.em.0.tx_abs_int_delay=0
Still getting errors, so I also added:
net.inet.ip.intr_queue_maxlen=4096
net.route.netisr_maxqlen=1024
and
kern.ipc.nmbclusters=655360
Also tried with rx_processing_limit set to -1 on all em interfaces, still getting errors.
Looking at the shape of the error and packet graphs, there seems to be a correlation between the number of packets per second on em0 and the height of the error "spikes" on the error graph. These spikes are spread throughout the day, with spaces (zones with no errors) of various lengths (10 minutes ... 2 hours spaces within the last 24 hours), but sometimes there are errors even in the lowest kpps times of the day.
em0 and em1 error times are correlated, with all errors on the graph for em0 having a smaller corresponding error spike on em1 at the same time, and sometimes an error spike on em2.
The old router was seeing about the same traffic, and had em0, em1, re0 and re1 network cards, and was only seeing errors on the em cards. It was running 7.2-PRERELEASE/i386
Any suggestions would be greatly appreciated. Please note that this is a live router, and I can't reboot it (unless absolutely necessary). Tuning that can be applied without rebooting will be tried first.
Here are some more details:
Trimmed output of netstat -ni (sorry if there are line breaks):
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
em0 1500 <Link#1> 00:14:22:xx:xx:xx 19744458839 15494721 24284439443 0 0
em1 1500 <Link#2> 00:14:22:xx:xx:xx 12832245469 123181 10105031790 0 0
em2 1500 <Link#3> 00:04:23:xx:xx:xx 12082552403 10964 10339416865 0 0
em3 1500 <Link#4> 00:04:23:xx:xx:xx 79912337 0 48178737 0 0
Relevant part of pciconf -vl:
em0@pci0:6:7:0: class=0x020000 card=0x016d1028 chip=0x10768086 rev=0x05 hdr=0x00
vendor = 'Intel Corporation'
device = '82541EI Gigabit Ethernet Controller'
class = network
subclass = ethernet
em1@pci0:7:8:0: class=0x020000 card=0x016d1028 chip=0x10768086 rev=0x05 hdr=0x00
vendor = 'Intel Corporation'
device = '82541EI Gigabit Ethernet Controller'
class = network
subclass = ethernet
em2@pci0:9:4:0: class=0x020000 card=0x10128086 chip=0x10108086 rev=0x01 hdr=0x00
vendor = 'Intel Corporation'
device = '82546EB Dual Port Gigabit Ethernet Controller (Copper)'
class = network
subclass = ethernet
em3@pci0:9:4:1: class=0x020000 card=0x10128086 chip=0x10108086 rev=0x01 hdr=0x00
vendor = 'Intel Corporation'
device = '82546EB Dual Port Gigabit Ethernet Controller (Copper)'
class = network
subclass = ethernet
Kernel messages after sysctl dev.em.0.stats=1:
(note that I've removed the lines which only showed zeros in the second and third outputs)
em0: Excessive collisions = 0
em0: Sequence errors = 0
em0: Defer count = 0
em0: Missed Packets = 15435312
em0: Receive No Buffers = 16446113
em0: Receive Length Errors = 0
em0: Receive errors = 1
em0: Crc errors = 2
em0: Alignment errors = 0
em0: Collision/Carrier extension errors = 0
em0: RX overruns = 96826
em0: watchdog timeouts = 0
em0: RX MSIX IRQ = 0 TX MSIX IRQ = 0 LINK MSIX IRQ = 0
em0: XON Rcvd = 0
em0: XON Xmtd = 0
em0: XOFF Rcvd = 0
em0: XOFF Xmtd = 0
em0: Good Packets Rcvd = 19002068797
em0: Good Packets Xmtd = 23168462599
em0: TSO Contexts Xmtd = 0
em0: TSO Contexts Failed = 0
[later]
em0: Excessive collisions = 0
em0: Missed Packets = 15459111
em0: Receive No Buffers = 16447082
em0: Receive errors = 1
em0: Crc errors = 2
em0: RX overruns = 96835
em0: Good Packets Rcvd = 19165047284
em0: Good Packets Xmtd = 23386976960
[later]
em0: Excessive collisions = 0
em0: Missed Packets = 15470583
em0: Receive No Buffers = 16447686
em0: Receive errors = 1
em0: Crc errors = 2
em0: RX overruns = 96840
em0: Good Packets Rcvd = 19255466068
em0: Good Packets Xmtd = 23519004546
Machine #2
I'm also seeing input errors on another machine, a Core 2 Duo E8200 CPU with 2 em cards, this time connected via PCI Express. This machine handles less traffic, and errors mostly appear on em0, which does NOT use vlans. All of the traffic goes on to em1 which does use vlans, but has recorded about 10% of the errors on em0. Also, netgraph is not used at all on this machine. Only hw.em.rxd, hw.em.txd and the dev.em.*.rx_processing_limit tunables were set for this machine.
Relevant info for machine #2:
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
em0 1500 <Link#1> 00:1b:21:xx:xx:xx 3095638890 12762 2604519812 0 0
em1 1500 <Link#2> 00:1b:21:xx:xx:xx 2608953742 1636 2998185465 0 0
em0@pci0:4:0:0: class=0x020000 card=0x10838086 chip=0x10b98086 rev=0x06 hdr=0x00
vendor = 'Intel Corporation'
device = '82572EI PRO/1000 PT Desktop Adapter (Copper)'
class = network
subclass = ethernet
em1@pci0:3:0:0: class=0x020000 card=0x10838086 chip=0x10b98086 rev=0x06 hdr=0x00
vendor = 'Intel Corporation'
device = '82572EI PRO/1000 PT Desktop Adapter (Copper)'
class = network
subclass = ethernet
em0: Excessive collisions = 0
em0: Sequence errors = 0
em0: Defer count = 402
em0: Missed Packets = 12762
em0: Receive No Buffers = 0
em0: Receive Length Errors = 0
em0: Receive errors = 0
em0: Crc errors = 0
em0: Alignment errors = 0
em0: Collision/Carrier extension errors = 0
em0: RX overruns = 237
em0: watchdog timeouts = 0
em0: RX MSIX IRQ = 0 TX MSIX IRQ = 0 LINK MSIX IRQ = 0
em0: XON Rcvd = 249
em0: XON Xmtd = 244
em0: XOFF Rcvd = 402
em0: XOFF Xmtd = 261
em0: Good Packets Rcvd = 3092053709
em0: Good Packets Xmtd = 2622962119
em0: TSO Contexts Xmtd = 12760095
em0: TSO Contexts Failed = 0
Thank you for your time.
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