Intel e1000e Linux Driver Special characteristic of anInterruptThrottleRate Parameter

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2011/11/21

1

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AuthorT.Oshima

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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PSG-20111118-1

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1/18

Abstract.
The parameter of 10 exists and it is known for the e1000e device driver (1.2.7. k2.0) used by
RedHawk 6.0 (kernel 2.6.36.4) that a performance will change.
In this paper, I clarify the special characteristic of the InterruptThrottleRate parameter (I call thefollowing ITR) which restricts the interrupt Numbers of the second bits which I generate by areceiving packet.

InterruptThrottleRate parameter
The InterruptThrottleRate parameter which can control the numbers of times of an interrupt of thesecond bit which an adaptor generates by a receiving packet exists in an e1000e driver.
1.2.7. In k2.0, InterruptThrottleRate can carry out a Contains-messages-which-match Set Value.
0,1,3,4,100～100000 （Default Value: 3）
0：
off
1：
dynamic,3：
dynamic conservative4：
simplified balancing
100～100000：
Interrupts Number (Hz)The driver has a mode of three which adjusts InterruptThrottleRate to a Dynamic based onreceiving traffic. (1 ,3 or 4 )An algorithm classifies each space character of receiving traffic into a Classes, and it adjusts thenumbers of times of a reception so that it may become a best in the type of the traffic.
The Classeses defined are "Bulk traffic", "Low latency", and "Lowest latency", and are thefollowing classes.
The algorithm classifies the incoming traffic every interval into classes. Once the class isdetermined, the InterruptThrottleRate value is adjusted to suit that traffic type the best. There arethree classes defined:"Bulk traffic", for large amounts of packets of normal size; "Low latency", for small amounts oftraffic and/or a significant percentage of small packets; and "Lowest latency", for almost completely
small packets or minimal traffic.

Title

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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Test method
Test 1 UDP unicast.
I connect two sets of iHawk systems to a direct with a crossing cable, and I measure thetransceiver time 10000 times, changing a transmitting sizes by UDP message, and calculate the meantime.
I perform a measurement by a client-side, and transmit to the repeat packets, every echo serverof the sizes of an any, and an echo server echoes back a receiving packet as it is to a client-side.
At this time, a measurement client uses Intel/e 1000e and uses Broadcom for an echo server.
Measurement Client
DELL T5500
Intel Corporation
82571EB
Gigabit Ethernet

Echo ServerStartTime
Send(Len)->Recv(Len)
Recv(Len)<-Send(Len)
EndTimebps=Len*16/(EndTime-StartTime)

DELL T5500
Broadcom Corporation
NetXtremeBCM5761
Gigabit Ethernet

Test 2 TCP unicast
I connect two sets of iHawk systems to a direct with a crossing cable, and I measure thetransceiver time 10000 times, changing a transmitting sizes by TCP message, and calculate the meantime.
I perform a measurement by a client-side, and transmit to the repeat packets, every echo serverof the sizes of an any, and an echo server echoes back a receiving packet as it is to a client-side.
At this time, a measurement client uses Intel/e 1000e and uses Broadcom for an echo server.
Measurement Client
DELL T5500
Intel Corporation
82571EB
Gigabit Ethernet

Echo ServerStartTime
Send(Len)->Recv(Len)
Recv(Len)<-Send(Len)
EndTimebps=Len*16/(EndTime-StartTime)

DELL T5500
Broadcom Corporation
NetXtremeBCM5761
Gigabit Ethernet

Test3 UDP Broadcast
A program is only a Sending. I measure the sending-out timing of an On The Network. In addition,
1472 bytes becomes a frames maximum length of a physical layer.
I used Astec-Eyes for the capture program. (http://www.asteceyes.com/ENGLISH/)
Measurement Client
T5500
Intel Corporation
82571EB
Gigabit Ethernet

Title

Capture Server
Len=1472;
Send(Len)->Recv(Len)Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

DELL PRESISION M6300
Broadcom Corporation
NetXtremeBCM57xx
Gigabit Ethernet

PSG-20111118-1

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The result of test1 (UDP unicast: half-duplex)
1000
ITR=0
900

ITR=4
8000Hz

ITR=3
Default

800

ITR=42000Hz700

600
Mbits/Sec

ITR=0
ITR=1
ITR=3

500

ITR=4
ITR=1000
400

ITR=10000
ITR=100000

300
ITR=1000
200

100

0
0

10000

20000

30000 40000
Bytes

50000

60000

n ITR=zero and default ITR=three, I can understand carrying out maximum 40% receiving performance
reduction so that clearly also from the above-mentioned graphs. Moreover, since a performance will
deteriorate rapidly if the is equal to which that it is near about 40 K byte can also understand, andthis threshold level are exceeded, receiving ITR=1000, i.e., a 1kHz interrupt restriction, needs
sufficient examination for a setups of InterruptThrottleRate. In this test, at the is equal to and UDP
Title

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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which are using basic-programming-system=Length/Time, in order for there not to be a sliding
window and DelayedACK, note that the Rate of a halfduplex communication is measured.

Length
2
4
8
16
32
64
128
256
512
1024
2048
3072
4096
5120
6144
7168
8192
9216
10240
16384
20480
30720
32768
40960
51200
61440
65507

Title

Intel Corporation 82571EB Gigabit EthernetTransfer Speed (Mbits/Sec)
ITR=0
ITR=1
ITR=3
ITR=4
ITR=1000 ITR=10000 ITR=100000
0.445663 0.382572 0.348723 0.258305 0.032025 0.323423
0.404999
0.892073 0.77235
0.703390.141199 0.064102 0.651809
0.817768
1.781683 1.543725 1.427716 0.256791 0.128201 1.303484
1.635693
3.56003
3.086654 2.885752 0.513591 0.256402 2.607257
3.270395
7.050438 6.166713 5.883353 1.027169 0.512801 5.214301
6.540131
13.83737 12.33311 10.85892 2.054366 1.025608 10.42784
13.07769
26.92293 24.6646
20.84139 4.108666 2.051238 20.84014
26.11139
50.61077 49.1882
41.67964 8.217369 4.1025
41.66972
46.42407
91.47952 83.36098 83.35953 16.43445 8.205053 83.35148
89.77731
173.4247 110.5933 110.5788 32.86979 16.41002 82.70287
157.8855
226.7988 221.0206 221.0182 65.74389 32.82117 165.3903
221.1074
291.3125 248.0967 248.0854 98.61468 49.2316
248.0859
277.8257
351.5137 330.7917 330.7787 131.4866 65.64192 330.7772
342.8074
383.5102 336.2146 333.0571 164.3654 82.0533
286.1853
383.8227
450.8901 396.4216 396.2313 197.2365 98.46375 329.9357
439.3302
484.999462.2186 462.1682 230.1122 114.8746 384.9114
479.0485
486.3491 439.9238 439.7418 262.983
131.2859 439.8981
477.3324
515.2482 494.3788 494.3414 295.8481 147.696
494.9076
506.9542
544.117328.9062 328.8973 328.7335 164.1069 444.0793
533.1537
606.6036 526.2272 526.2021 525.9484 262.5739 526.7969
603.9892
654.6596 504.5338 494.0084 437.8894 328.2176 548.7808
643.133
706.9754 611.7206 611.6741 492.3353 492.3422 618.5514
693.4426
700.0705 587.1763 579.2037 525.1538 525.1467 657.7288
694.2891
725.9821 656.7748 656.7788 656.4529 656.0693 657.5389
719.3018
754.5919 656.582
656.5789 546.9639 409.9492 691.7988
748.6166
759.3838 656.444
656.4326 656.0687 491.8033 704.133
753.5389
771.7102 699.9059 699.9042 699.3769 524.3528 749.0866
764.781

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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The UDP redirection result at the time of making it link to below by 100.00Mbits/Sec as reference
data is shown.
Here, I can understand that the is equal to and performance inequality which also show the data of
Broadcom for the Compare are the same as the tendency of a certain is equal to and an ITR=zero If
You are.
100
9080

Rate(Mbits/sec)

70
ITR0

60

ITR1

50

ITR3
ITR4

40

ITR10000
30

Broadcom

20
10

9984

9472

8960

8448

7936

7424

6912

6400

5888

5376

4864

4352

3840

3328

2816

2304

1792

768

1280

256

0

The following displays jitter of the transmitting space character at the time of a 64Kbytes redirection
as a default parameter.
When it compares with Broadcom, and that jitter of intel is small can understand, however the total
is searched for, the value of the way of broadcom is a Small. (Namely, transmitting Time Short) Thisis clear also from a transmission-rate-UDP transfer size graphs.

Intel totaltime Bradcom total time
0.005205
0.005114

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Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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The jitter time at the time of a Continuous Sending(Intel/ITR=3)0.000250.00020.00015intel

0.0001

bradcom

0.000050
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43

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Intel Corporation 82571EB Gigabit Ethernet (Mbits/Sec)

Length ITR0
ITR1
ITR3
ITR4
ITR10000
256
16.9674
16.4922 16.49235 9.708307
27.51581
512 44.23792
32.98685 32.98897 16.43402
43.50932
768 55.51161
49.48384 49.47324 24.65147
55.43941
1024 60.15921
32.89418 32.89101 32.86467
58.90783
1280 64.62678
41.11101 41.10985 41.08594
64.23397
1536 67.03746
49.32381 49.33237 49.29675
66.59999
1792
68.2278
57.54407 57.53704 57.50872
67.01961
2048
70.6366
65.76419 65.76482 65.72311
70.01744
2304 72.78924
64.57396
63.4049 59.27608
72.42791
2560 74.94909
54.75501 54.75459 41.02572
74.66686
2816 76.50701
60.23016 60.22309 45.12645
75.64286
3072 78.36484
65.7052 65.70331 49.22868
78.02235
3328 77.97153
71.17345 71.16791 53.33181
77.44544
3584 79.01536
76.65117 76.64858 57.43342
78.77742
3840 80.02711
61.57851 61.56721 61.53652
79.55971
4096 80.92414
65.67061
65.6692 65.63817
80.19684352 81.72227
69.77187 69.77459 69.74202
81.22963
4608 83.07812
73.87911 73.87748 73.84302
82.93492
4864 82.32886
77.97795 77.97973 77.93833
82.13995120 82.88283
82.08238 82.08295 82.03977
82.39776
5376 83.60062
68.94054 68.93471 57.41837
82.98157
5632 84.12014
72.21587 72.21811 60.13803
83.67871
5888 84.59796
75.50041 75.50017 62.87197
84.33846
6144 84.37777
78.78123
78.7831 65.60578
84.33033
6400 84.79246
82.06206 82.06214
68.33984.44519
6656 85.20769
85.09571 85.11399 71.07303
84.75218
6912 85.61047
73.84632 73.84348 73.80641
85.29808
7168 85.99587
76.57891 76.57643 76.54017
85.80267424 86.16799
79.31274 79.31194 79.26785
85.7858
7680 86.01533
82.04483 82.04753 82.00673
85.5895
7936 86.30098
84.77394 84.77375
84.7347
86.00405
8192 86.50314
75.06367 75.00759 65.63918
86.36874
8448 86.92805
77.34743 77.34842 67.63777
86.81895
8704 87.18176
79.6922 79.69001 69.68816
86.85779
8960
87.562982.03391 82.03402 71.73695
87.61442
9216 87.20295
84.37553 84.37677 73.78675
86.94799
9472 87.46169
86.72042 86.72047 75.83651
87.28582
9728
87.6876
77.92899 77.92749 77.88622
87.51507
9984 87.92208
79.97765
79.9777 79.93574
87.61378
10240 88.12813
82.0275 82.02733 81.98313
87.8205

Title

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

Broadcom Corporation
NetXtreme BCM5761 Gigabit
Ethernet(Mbits/Sec)
Broadcom
24.45411
38.52117
47.57609
53.51725
57.87698
60.31472
63.05549
65.73954
67.91170.13655
71.75188
73.81533
73.96251
75.19904
76.22007
77.10481
77.951679.54405
79.1185
79.80375
80.42927
80.99922
81.46523
81.549382.0533
82.49404
82.90762
83.23947
83.29252
83.56122
83.979184.15515
84.54815
84.78911
85.16634
85.03961
85.31675
85.55258
85.7516285.92413

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Intel（Sec）
Bradcom（Sec）
0.0001030.000024
0.000125
0.0001010.0001020.000112
0.000147
0.000196
0.000093
0.000021
0.000143
0.000228
0.000127
0.000022
0.0001330.000220.000088
0.000024
0.000148
0.000222
0.000112
0.000022
0.000132
0.000217
0.000124
0.000023
0.00010.000230.000125
0.000024
0.000137
0.000170.0001080.000095
0.000135
0.000202
0.000139
0.000024
0.000110.000214
0.0001020.000024
0.000147
0.000228
0.00010.000024
0.000118
0.000131
0.000149
0.000215
0.000130.000023
0.000088
0.000219
0.000146
0.000024
0.000110.000221
0.0001410.000024
0.000117
0.0001410.000131
0.000201
0.000097
0.000026
0.000147
0.000214
0.000093
0.000028
0.000149
0.000220.000136
0.000027
0.000095
0.000235
0.0001290.000023
0.0001080.000205
0.000125
0.000028
0.000115
0.000219
0.0001010.000023

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The result of test 2 (TCP unicast: full-duplex)
2000

1800

1600

1400

1200
Mbits/Sec

ITR=0
ITR=1
ITR=3

1000

ITR=4
ITR=1000
800

ITR=10000
ITR=100000

600

400

200

0
0

10000

20000

30000 40000
Bytes

50000

60000

In an exam program, since the amount of send-receives / time is used and the Rate of afull-duplex transmission is measured, be careful of the Dot Screen that the upper is 2.0GBits/Sec.
If it says from a result and a packet size will be below TwentyK, ITR=zero shows the performancewith sufficient ITR=fourth by more than it.

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Length
2
4
8
16
32
64
128
256
512
1024
2048
3072
4096
5120
6144
7168
8192
9216
10240
16384
20480
30720
32768
40960
51200
61440
65507

Title

Intel Corporation 82571EB Gigabit Ethernet 転送速度(Mbits/Sec)
ITR=0
ITR=1
ITR=3
ITR=4
ITR=1000 ITR=10000 ITR=100000
0.392392 0.392562 0.325785
0.12647 0.032052
0.325734
0.363132
0.782312 0.777854 0.651663 0.128411 0.064104
0.651227
0.726243
1.56694 1.552846 1.303278 0.256808 0.128203
1.302377
1.452397
3.09738 2.974703 2.606585 0.513611 0.256405
2.604593
2.902889
6.147374 5.811571 5.213515 1.027249
0.512815.210136
5.803423
12.16617 11.44435 10.42614 2.054377 1.025625
10.42055
11.58401
23.74798 22.52441 20.84943 4.108895 2.051253
20.84287
23.11815
44.70264 43.43888 41.68168 8.217524 4.102553
41.67646
43.70521
84.89498 63.81365 56.97253 16.43497
8.205183.30664
84.91557
138.5681 110.5373
110.562 32.87044
16.410382.68659
131.7549
203.6252 1506.055 1542.612 65.74286 32.82137
165.4096
210.6821
974.3314
1726.34
1533.8 98.62324 49.23451
248.1096
1717.274
1598.704 1726.203 1537.271
131.493 65.64696
744.3475
1765.598
1827.698 1739.751 1643.406 166.2111 82.05789
1820.525
1776.178
1848.619 1755.479 1120.908 200.5862 98.47057
1710.643
1762.681
1836.974 1762.744 1736.145 233.4183 114.8825
1772.168
1769.95
1821.18 1754.143 1763.315 268.1716
131.29339.2365
1753.885
1814.903 1752.443 1826.259 300.6274 147.7021
540.3937
1752.976
1785.531 1816.726 1838.899 333.8434 164.1105
1682.847
1759.677
1755.401 1813.815 1778.345 797.1355
1196.25
1821.866
1744.823
1740.806 1762.513 1755.282 1746.592 1745.858
1839.415
1747.303
1791.417 1739.104 1840.787
1821.26 1437.386
1825.057
1745.214
1855.773 1730.417 1828.552
1828.98 1522.715
1813.904
1744.798
1832.078 1749.624 1820.879
1830.3 1762.688
1806.925
1763.646
1833.47 1825.872 1820.733 1819.396 1803.092
1786.51831.184
1817.766 1820.327 1807.633 1817.083 1814.945
1794.55
1825.384
1827.222 1816.341 1819.187 1820.362 1805.853
1811.484
1825.35

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The result of test 3 (UDP broadcast).
Below, the result of test 3 is shown. A time-axis expresses the amount of data per first millisecond
by Bits/Sec.
ITU=0

ITU=1

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of an InterruptThrottleRate parameter

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ITU=3

ITU=4

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Intel e1000e Linux Driver Special characteristic No
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If its attention is paid to the time-axis of a graphs, he can understand that the times to thetermination of a redirection differ, and I can read that it is as high as this Time Short thing in Burst
nature.
A data with this late Controls effective in the following is shown.
The ordinate of a graphs is a transmitting time between packets, and is shown by the Logs Scaletype.
In an ITU100.00 If You are, I can read easily that the bandwidth restriction has occurred in about 10
ms (100.00Hz).

The transmitting interval for every ITR
0.01

Time(Sec)

0.001
ITU=100
ITU=1000

0.0001

ITU=10000
ITU=100000

0.00001

0.000001

Summary
From the exam result, it became clear in the real-time use that setting to ITR=0 was desirable.
In addition, in order to set this parameter to a ramp-up period, I add the following lineses tomodules.conf.
alias eth0 e1000e
alias eth1 e1000e
alias eth2 e1000e
alias eth3 e1000e
options e1000e InterruptThrottleRate=0,0,0,0
In addition, when a the port will be two or more sheets, it is necessary to divide a parameter with acomma.

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The further description of a parameter
Linux* Driver for Intel(R) Network Connection===============================================================
Intel Gigabit Linux driver.
Copyright(c) 1999 - 2010 Intel Corporation.
Contents========- Identifying Your Adapter- Command Line Parameters- Additional Configurations- Support
Identifying Your Adapter========================The e1000e driver supports all PCI Express Intel(R) Gigabit Network
Connections, except those that are 82575, 82576 and 82580-based*.
* NOTE: The Intel(R) PRO/1000 P Dual Port Server Adapter is supported by the e1000 driver, not the e1000e driver due
to the 82546 part being used behind a PCI Express bridge.
For more information on how to identify your adapter, go to the Adapter & Driver ID Guide at:
http://support.intel.com/support/go/network/adapter/idguide.htm
For the latest Intel network drivers for Linux, refer to the following website. In the search field, enter your adapter nameor type, or use the networking link on the left to search for your adapter:
http://support.intel.com/support/go/network/adapter/home.htm
Command Line Parameters=======================The default value for each parameter is generally the recommended setting, unless otherwise noted.
NOTES: For more information about the InterruptThrottleRate, RxIntDelay, TxIntDelay, RxAbsIntDelay, andTxAbsIntDelay parameters, see the application note at:
http://www.intel.com/design/network/applnots/ap450.htm
InterruptThrottleRate--------------------Valid Range:
0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative,
4=simplified balancing)
Default Value: 3
The driver can limit the amount of interrupts per second that the adapter will generate for incoming packets. It does thisby writing a value to the adapter that is based on the maximum amount of interrupts that the adapter will generate persecond.
Setting InterruptThrottleRate to a value greater or equal to 100 will program the adapter to send out a maximum of thatmany interrupts per second, even if more packets have come in. This reduces interrupt load on the system and can lower
CPU utilization under heavy load, but will increase latency as packets are not processed as quickly.
The driver has two adaptive modes (setting 1 or 3) in which it dynamically adjusts the InterruptThrottleRate value basedon the traffic that it receives. After determining the type of incoming traffic in the last timeframe, it will adjust theInterruptThrottleRate to an appropriate value
for that traffic.
The algorithm classifies the incoming traffic every interval into classes. Once the class is determined, theInterruptThrottleRate value is adjusted to suit that traffic type the best. There are three classes defined:"Bulk traffic", for large amounts of packets of normal size; "Low latency", for small amounts of traffic and/or a significant
percentage of small packets; and "Lowest latency", for almost completely small packets or minimal traffic.
In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 for traffic that falls in class "Bulk traffic".
If traffic falls in the "Low latency" or "Lowest latency" class, the InterruptThrottleRate is increased stepwise to 20000.
This default mode is suitable for most applications.
For situations where low latency is vital such as cluster or grid computing, the algorithm can reduce latency even morewhen InterruptThrottleRate is set to mode 1. In this mode, which operates the same as mode 3, the InterruptThrottleRate
will be increased stepwise to 70000 for traffic in class "Lowest latency".
In simplified mode the interrupt rate is based on the ratio of Tx and Rx traffic. If the bytes per second rate isapproximately equal the interrupt rate will drop as low as 2000 interrupts per second. If the traffic is mostly transmit or
mostly receive, the interrupt rate could be as high as 8000.
Setting InterruptThrottleRate to 0 turns off any interrupt moderation and may improve small packet latency, but isgenerally not suitable for bulk throughput traffic.
NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay andRxAbsIntDelay parameters. In
other words, minimizing the receive and/or transmit absolute delays does not force the controller to generate moreinterrupts than what the Interrupt Throttle Rate allows.
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NOTE: When e1000e is loaded with default settings and multiple adapters are in use simultaneously, the CPU utilization
may increase non-linearly. In order to limit the CPU utilization without impacting the overall throughput, we recommendthat you load the driver as follows:
modprobe e1000e InterruptThrottleRate=3000,3000,3000
This sets the InterruptThrottleRate to 3000 interrupts/sec for the first, second, and third instances of the driver.
The range of 2000 to 3000 interrupts per second works on a majority ofsystems and is a good starting point, but
the optimal value will be platform-specific. If CPU utilization is not a concern, use RX_POLLING (NAPI) and default driver
settings.
RxIntDelay---------Valid Range:
0-65535 (0=off)
Default Value: 0This value delays the generation of receive interrupts in units of 1.024 microseconds. Receive interrupt reduction can
improve CPU efficiency if properly tuned for specific network traffic. Increasing this value adds extra latency to frame
reception and can end up decreasing the throughput of TCP traffic. If the system is reporting dropped receives, thisvalue may be set too high, causing the driver to run out of available receive descriptors.
CAUTION: When setting RxIntDelay to a value other than 0, adapters may hang (stop transmitting) under certain network
conditions. If this occurs a NETDEV WATCHDOG message is logged in the system event log. In addition, the controller
is automatically reset, restoring the network connection. To eliminate the potential for the hang ensure that RxIntDelayis set to 0.
RxAbsIntDelay------------Valid Range:
0-65535 (0=off)
Default Value: 8This value, in units of 1.024 microseconds, limits the delay in which a receive interrupt is generated. Useful only if
RxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is received within the set
amount of time. Proper tuning, along with RxIntDelay, may improve traffic throughput in specific network conditions.
TxIntDelay---------Valid Range:
0-65535 (0=off)
Default Value: 8This value delays the generation of transmit interrupts in units of 1.024 microseconds. Transmit interrupt reduction can
improve CPU efficiency if properly tuned for specific network traffic. If thesystem is reporting dropped transmits, this value may be set too high causing the driver to run out of available transmit
descriptors.
TxAbsIntDelay------------Valid Range:
0-65535 (0=off)
Default Value: 32
This value, in units of 1.024 microseconds, limits the delay in which a transmit interrupt is generated. Useful only if
TxIntDelay is non-zero, this value ensures that an interrupt is generated after the initial packet is sent on the wire within
the set amount of time. Proper tuning, along with TxIntDelay, may improve traffic throughput in specific network
conditions.
Copybreak--------Valid Range:
0-xxxxxxx (0=off)
Default Value: 256
Driver copies all packets below or equaling this size to a fresh Rx buffer before handing it up the stack.
This parameter is different than other parameters, in that it is a single (not 1,1,1 etc.) parameter applied to all driver
instances and it is also available during runtime at /sys/module/e1000e/parameters/copybreak
SmartPowerDownEnable-------------------Valid Range: 0-1
Default Value: 0 (disabled)
Allows PHY to turn off in lower power states. The user can set this parameter in supported chipsets.
KumeranLockLoss--------------Valid Range: 0-1
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Default Value: 1 (enabled)
This workaround skips resetting the PHY at shutdown for the initial silicon releases of ICH8 systems.
IntMode------Valid Range: 0-2 (0=legacy, 1=MSI, 2=MSI-X)
Default Value: 2
Allows changing the interrupt mode at module load time, without requiring a recompile. If the driver load fails to enable a
specific interrupt mode, the driver will try other interrupt modes, from least to most compatible. The interrupt order is
MSI-X, MSI, Legacy. If specifying MSI (IntMode=1) interrupts, only MSI and Legacy will be attempted.
CrcStripping-----------Valid Range: 0-1
Default Value: 1 (enabled)
Strip the CRC from received packets before sending up the network stack. If you have a machine with a BMC enabled but
cannot receive IPMI traffic after loading or enabling the driver, try disabling this feature.
WriteProtectNVM--------------Valid Range: 0-1
Default Value: 1 (enabled)
Set the hardware to ignore all write/erase cycles to the GbE region in the ICHx NVM (non-volatile memory). This feature
can be disabled by the WriteProtectNVM module parameter (enabled by default) only after a hardware reset, but themachine must be power cycled before trying to enable writes.
Note: the kernel boot option iomem=relaxed may need to be set if the kernel config option CONFIG_STRICT_DEVMEM=y, if
the root user wants to write the NVM from user space via ethtool.
Additional Configurations=========================
Jumbo Frames-----------Jumbo Frames support is enabled by changing the MTU to a value larger than the default of 1500.
command to increase the MTU size.
For example:

Use the ifconfig

ifconfig eth<x> mtu 9000 up
This setting is not saved across reboots.
Notes:- The maximum MTU setting for Jumbo Frames is 9216. This value coincides with the maximum Jumbo Frames size of9234 bytes.
- Using Jumbo Frames at 10 or 100 Mbps is not supported and may result in poor performance or loss of link.
- Some adapters limit Jumbo Frames sized packets to a maximum of 4096 bytes and some adapters do not support
Jumbo Frames.
Ethtool------The driver utilizes the ethtool interface for driver configuration and diagnostics, as well as displaying statisticalinformation. We strongly recommend downloading the latest version of Ethtool at:
http://sourceforge.net/projects/gkernel.
Speed and Duplex---------------Speed and Duplex are configured through the Ethtool* utility. For instructions,refer to the Ethtool man page.

Enabling Wake on LAN* (WoL)--------------------------WoL is configured through the Ethtool* utility. For instructions on enabling WoL with Ethtool, refer to the Ethtool man
page.
WoL will be enabled on the system during the next shut down or reboot.
For this driver version, in order to enable WoL, the e1000e driver must be loaded when shutting down or rebooting thesystem.
In most cases Wake On LAN is only supported on port A for multiple port adapters. To verify if a port supports Wake on
LAN run ethtool eth<X>.

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Support=======For general information, go to the Intel support website at:www.intel.com/support/
or the Intel Wired Networking project hosted by Sourceforge at:
http://sourceforge.net/projects/e1000
If an issue is identified with the released source code on the supported kernel with a supported adapter, email the specificinformation related to the issue to e1000-devel@lists.sf.net

Title

Intel e1000e Linux Driver Special characteristic No
of an InterruptThrottleRate parameter

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