In AIX 7.1 TL1 SP5, new network tuning parameter is introduced - init_high_wat. I could not find any details (google, man pages) about this parameter and how it can be used to improve network performance.
Anyone has any idea?
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3 replies Latest Post - 2012-10-04T05:32:52Z by cggibbo
Pinned topic AIX 7.1/6.1 init_high_wat network tuning parameters
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Updated on 2012-10-04T05:32:52Z at 2012-10-04T05:32:52Z by cggibbo
IgnacioDB 270002WK605 PostsACCEPTED ANSWER
Re: AIX 7.1/6.1 init_high_wat network tuning parameters2012-09-19T11:41:02Z in response to swarzesHi swazes, I suppose that is not a tunning to directly improve network performance, its a tunning to prevent that peaks of network activity impacts on CPU consumption.
I think that is the same concept of I/O pacing for network performance, using pinned memmory to support high network traffic workloads.
cggibbo 270000TMUJ27 PostsACCEPTED ANSWER
Re: AIX 7.1/6.1 init_high_wat network tuning parameters2012-10-04T05:32:52Z in response to swarzes
- no -h init_high_wat
Specifies the initial high water mark value for 128K bytes bucket per cpu. If init_high_wat is set, it will pin more initial memory for internal 128K bytes bucket than default behavior.
Range: 0 - 10
The init_high_wat attribute represents a percentage of the thewall per cpu. For example, if init_high_wat is set to 2, thewall is 8 gigabytes, and it has 4 logic cpus, the number of 128 kilobytes in size per cpu is: ((8 * 1024 * 1024 * 1024) / 4) / (128 * 1024) = 16384. 2% of 16386 is 327. So the initial high water value for 128 kilobytes in size per cpu is 327. WARNING: This is an extremely sensitive option and can have adverse impact on your system performance if set unresaonably high. Please use extreme caution in modifying this option.