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nikhil
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high irq usage how to fix

Thu Jun 02, 2011 4:16 pm

Hi irq usage . using dell 2950 (dual quad core cpus) 5.0rc4 with intel 82576 based 4 port card pci express - i htought this was msi-x and should not eat up so many irqs and cpu cycles . doing 75kpps -90kpps out and 90kpps in . multicpu is on

total-memory: 1943140KiB
cpu: "Intel(R)"
cpu-count: 8
cpu-frequency: 2494MHz
cpu-load: 49%

/system resource irq?
# IRQ USERS CPU ACTIVE-CPU COUNT
0 1 i8042 auto 7 2
1 4 serial auto 7 4
2 9 acpi auto 7 0
3 12 i8042 auto 7 4
4 14 ide0 auto 7 0
5 20 usb5 auto 7 86
usb3
6 21 usb4 auto 7 23
usb2
usb1
7 23 ata_piix auto 7 74197
8 40 aerdrv auto 7 0
9 41 aerdrv auto 7 0
10 42 aerdrv auto 7 0
11 43 aerdrv auto 7 0
12 44 aerdrv auto 7 0
13 45 aerdrv auto 7 0
14 51 ether1 0 0 4
15 52 eth2-TxRx-0 auto 7 17781
16 53 eth2-TxRx-1 auto 7 17438
17 54 eth2-TxRx-2 auto 7 17464
18 55 eth2-TxRx-3 auto 7 17409
19 56 eth2-TxRx-4 auto 7 17453
20 57 eth2-TxRx-5 auto 7 17410
21 58 eth2-TxRx-6 auto 7 17410
22 59 eth2-TxRx-7 auto 7 17779
23 60 ether5 4 4 41431
24 61 ether2 5 5 1
25 62 eth3-TxRx-0 1 1 45961
26 63 eth3-TxRx-1 auto 7 21480
27 64 eth3-TxRx-2 auto 7 27693
28 65 eth3-TxRx-3 auto 7 62143
29 66 eth3-TxRx-4 auto 7 17208
30 67 eth3-TxRx-5 auto 7 87162
31 68 eth3-TxRx-6 auto 7 41112
32 69 eth3-TxRx-7 auto 7 95679
33 70 ether6 auto 6 26743
34 71 ether3 2 2 1
35 72 eth4-TxRx-0 auto 6 16720
36 73 eth4-TxRx-1 auto 6 15340
37 74 eth4-TxRx-2 auto 0 66215
38 75 eth4-TxRx-3 auto 1 46466
39 76 eth4-TxRx-4 auto 5 75324
40 77 eth4-TxRx-5 auto 6 34156
41 78 eth4-TxRx-6 auto 1 59448
42 79 eth4-TxRx-7 auto 5 61407
43 80 ether4 3 3 1
44 81 eth5-TxRx-0 auto 6 2888
45 82 eth5-TxRx-1 auto 4 49941
46 83 eth5-TxRx-2 auto 6 30318
47 84 eth5-TxRx-3 auto 6 42206
48 85 eth5-TxRx-4 auto 6 30322
49 86 eth5-TxRx-5 auto 0 66746
50 87 eth5-TxRx-6 auto 4 87596
51 88 eth5-TxRx-7 auto 7 99130

CPU LOAD IRQ DISK
0 47% 46% 0%
1 50% 50% 0%
2 35% 37% 0%
3 41% 43% 0%
4 38% 40% 0%
5 38% 40% 0%
6 79% 81% 0%
7 63% 65% 0%
/system resource cpu>

monitor traffic aggregate shows

rx-packets-per-second: 166270
rx-drops-per-second: 0
rx-errors-per-second: 0
rx-bits-per-second: 282.9Mbps
tx-packets-per-second: 166648
tx-drops-per-second: 0
tx-errors-per-second: 0
tx-bits-per-second: 271.6Mbps

/system resource pci partial paste below shows as 82576 based chip which does support msi-x !

# DEVICE VENDOR NAME IRQ
1 0d:00.1 Intel Corporation 82576 Gigabit Network Connection (rev: 1) 6
2 0d:00.0 Intel Corporation 82576 Gigabit Network Connection (rev: 1) 10
3 0c:00.1 Intel Corporation 82576 Gigabit Network Connection (rev: 1) 11
4 0c:00.0 Intel Corporation 82576 Gigabit Network Connection (rev: 1) 11
8 07:00.0 Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev: 18) 11
9 06:00.0 Broadcom EPB PCI-Express to PCI-X Bridge (rev: 195) 0
10 05:01.0 Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E2 (rev: 1) 0
11 05:00.0 Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E1 (rev: 1) 0
12 04:00.3 Intel Corporation 6311ESB/6321ESB PCI Express to PCI-X Bridge (rev: 1) 0
13 04:00.0 Intel Corporation 6311ESB/6321ESB PCI Express Upstream Port (rev: 1) 0
14 03:00.0 Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev: 18) 11
15 02:00.0 Broadcom EPB PCI-Express to PCI-X Bridge (rev: 195) 0


So what do i do to bring irq load down ? None of the change logs in the latest since rc4 suggest anything to do with irq/msi-x have been done
 
nikhil
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Re: high irq usage how to fix

Sun Jun 05, 2011 1:41 am

Anybody know how to reduce the IRQ usage. I have put in most of the information in the first post... Please help
 
nikhil
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Re: high irq usage how to fix

Tue Jun 14, 2011 3:29 pm

Upgraded to 5.4 but no use still have High irq usage
I did notice that some of our servers behind are sending high amount of udp packets but the router is still only handling 100kpps IN + 100kpps OUT with 8 cores we should have plenty of speed to spare. IRQ utilization is too much. Isnt there any machine where irq using the cpu can be reduced dramatically?
 
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martini
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Re: high irq usage how to fix

Tue Jun 14, 2011 11:18 pm

set the irq to different number of proccesor (from 0 to 7), change the "auto" to number of cpu on ethernet interfacec and tx-rx queue
 
nikhil
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Re: high irq usage how to fix

Wed Jun 15, 2011 12:12 am

so just randomly split the load across instead of using auto?p
Should I setup etherx interface on a separate cpu and tx-rx on separate cpu . eg
ether1 on cpu 0
eth1-rx1 on cpu1
eth1-rx2 on cpu2
xxxxx- and so on ?

I did try something but that didnt help too much.. the packets are so small and too many..

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