On Mon, 2010-08-09 at 15:36 -0700, Wyborny, Carolyn wrote:
> Hello,
>
> How do you have flow control configured for these ports? Has this been
> a problem since you've set the system up or is this new? If new, what
> has changed recently in your environment?
Hullo. :)
Flow control is not specifically configured; I use Cisco Cat 3750s so am
running with whatever they end up negotiating with the NICs:
[39309953.090015] eth1: Link is Up 1000 Mbps Full Duplex, Flow Control:
None
[39309953.114324] eth0: Link is Up 1000 Mbps Full Duplex, Flow Control:
None
[39309953.358634] eth3: Link is Up 1000 Mbps Full Duplex, Flow Control:
None
[39309953.762084] eth2: Link is Up 1000 Mbps Full Duplex, Flow Control:
None
Can you advise what the Cisco IOS config options (if any..) would be to
set flow control? 'show flowcontrol' tells me:
Port Send FlowControl Receive FlowControl RxPause TxPause
admin oper admin oper
--------- -------- -------- -------- -------- ------- -------
...
Gi1/0/17 Unsupp. Unsupp. off off 0 0
Gi1/0/18 Unsupp. Unsupp. off off 0 0
Gi1/0/19 Unsupp. Unsupp. off off 0 0
Gi1/0/20 Unsupp. Unsupp. off off 0 0
Meanwhile, I took the opportunity to reload the e1000e driver and
specify InterruptThrottleRate=1,1,1,1 in the hopes that the increased
ceiling of 70k interrupts/sec would minimise the dropped packets:
[39309887.935861] e1000e: Intel(R) PRO/1000 Network Driver - 0.3.3.3-k2
[39309887.935861] e1000e: Copyright (c) 1999-2008 Intel Corporation.
[39309887.935861] ACPI: PCI Interrupt 0000:15:00.0[A] -> GSI 16 (level,
low) -> IRQ 16
[39309887.935861] PCI: Setting latency timer of device 0000:15:00.0 to
64
[39309887.963861] 0000:15:00.0: Interrupt Throttling Rate (ints/sec) set
to dynamic mode
[39309888.115867] eth0: (PCI Express:2.5GB/s:Width x4) 00:23:7d:fb:df:1a
[39309888.115867] eth0: Intel(R) PRO/1000 Network Connection
[39309888.115942] eth0: MAC: 0, PHY: 4, PBA No: d51930-005
(... plus near-identical for eth1, 2, 3)
We are now into the quiet time for our site, but even having allowed up
to 70k interrupts/sec with mode 1, the dropped-packet count is still
rising quickly:
cor4:~# ifconfig eth3
eth3 Link encap:Ethernet HWaddr 00:24:81:7b:04:ac
UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
RX packets:17935406 errors:0 dropped:103128 overruns:0 frame:0
And yet the overall system interrupts/sec is still only hovering around
20k:
cor4:~# vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system--
----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 60 1291692 164312 346380 0 0 0 0 0 0 1 4 95 0
0 0 60 1291808 164312 346380 0 0 0 0 19582 856 0 7 92 0
0 0 60 1291312 164312 346380 0 0 0 0 19071 1028 0 7 93 0
0 0 60 1292752 164312 346380 0 0 0 0 19308 1034 1 8 91 0
0 0 60 1292048 164312 346380 0 0 0 0 20653 1085 0 9 91 0
If this is the case, would I be likely to see any benefit from setting
InterruptThrottleRate=0,0,0,0 ?
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Hang on... I just had a look in e1000e/param.c in the Debianised source
for 2.6.26 .. and found this....
case 1:
ndev_info(netdev,
"%s set to dynamic mode\n",
opt.name);
adapter->itr_setting = adapter->itr;
adapter->itr = 20000;
break;
case 3:
ndev_info(netdev,
"%s set to dynamic conservative
mode\n",
opt.name);
adapter->itr_setting = adapter->itr;
adapter->itr = 20000;
break;
Huh? Both modes 1 + 3 set ITR to 20000? I'm no kernel programmer but
shouldn't it be 70000 for mode 1?
gdh
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