Conflicting CPU frequency values detected

在测试IB网络中，遇到如下问题：

1.在一个节点上启动ib_write_bw

[root@storage2 ~]# ib_write_bw

------------------------------------------------------------------

RDMA_Write BW Test

Number of qps : 1

Connection type : RC

CQ Moderation : 50

Link type : IB

Mtu : 2048

Inline data is used up to 0 bytes message

local address: LID 0x04 QPN 0x38004d PSN 0x26358e RKey 0x70003000 VAddr 0x007f1986890000

remote address: LID 0x03 QPN 0x38004d PSN 0x4c35aa RKey 0x80003000 VAddr 0x007fa5ecb82000

2.在另一个节点上启动测试

[root@storage1 ~]# ib_write_bw 192.168.126.12

------------------------------------------------------------------

RDMA_Write BW Test

Number of qps : 1

Connection type : RC

TX depth : 300

CQ Moderation : 50

Mtu : 2048B

Link type : IB

Max inline data : 0B

rdma_cm QPs : OFF

Data ex. method : Ethernet

------------------------------------------------------------------

local address: LID 0x03 QPN 0x6c0053 PSN 0x38d98e RKey 0x50003000 VAddr 0x007facff0ed000

remote address: LID 0x04 QPN 0x2c004d PSN 0xd95310 RKey 0x58003000 VAddr 0x007f902e7d7000

------------------------------------------------------------------

#bytes #iterations BW peak[MB/sec] BW average[MB/sec]

Conflicting CPU frequency values detected: 1200.000000 != 2001.000000

65536 5000 0.00 0.00

------------------------------------------------------------------

3.运行后，没有结果，提示如下：

Conflicting CPU frequency values detected: 1200.000000 != 2001.000000

4.解决办法：

需要关闭两个节点上的cpuspeed服务。

[root@storage2 ~]# service cpuspeed stop

Disabling ondemand cpu frequency scaling: [ OK ]

[root@storage1 ~]# service cpuspeed stop

Disabling ondemand cpu frequency scaling: [ OK ]

关闭服务后，上述测试可以正常进行。

5.关于cpuspeed

【参考】http://linux.die.net/man/8/cpuspeed

cpuspeed用来根据运行情况，调整cpu的频率以降低功耗。