Originally posted by: swarzes

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?
#AIX-Forum

Originally posted by: IgnacioDB

Hi 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.

Regards
#AIX-Forum

Originally posted by: swarzes

Thanks IgnacioDB. Is there any way to disable this parameter or init_high_wat=0 means it is disabled?
#AIX-Forum

Originally posted by: cggibbo

1. no -h init_high_wat

Help for tunable init_high_wat:
Purpose:
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.

Values:
Default: 0
Range: 0 - 10
Type: Dynamic
Unit: %_of_thewall
Tuning:
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.
#AIX-Forum