Freitag November 25, 2005

N1GE 6 - A couple lines on halftime and usage
The usage stored in the sharetree is controlled by its halftime. The halftime can be configured by using the halftime parameter in the scheduler configuration. This parameter specifies the halftime of the usage in hours. 1 hour is the smallest halftime one can set. A setting of 0 will turn the decrease of the usage of, which means that it will always grow.

A short coming on this setting is, that all three usages (io, mem, cpu) are treated equally. The halflife_decay_list the way to overcome this short coming. It allows to set different decay rates for io, mem and cpu usage. The time in this list is specified in minutes and in addition allows to turn of past usage at all, when the time is set to a negative value. A zero means no decrease of usage. If a decay time of -1 is set, all past usage is removed right away and only the usage of the current running jobs is used during the sharetree computation.

The settings of the halflife_decay_list will override the halftime settings.

Some examples ('qconf -msconf'):

1) Using half_life_decay_list to get the same result as with halftime

    halftime                           24
    halflife_decay_list        cpu=1440:mem=1440:io=1440

2) Disabeling past usage

    halftime                           168
    halflife_decay_list        cpu=-1:mem=-1:io=-1

3) Disable past usage for mem the others have a halftime of 1 day

    halftime                           24
    halflife_decay_list        mem=-1

Important:

    More than parameter in the halflife_decay_list would crash the system until version 6.0u7. We fixed issue 1826 in 6.0u7

( Nov 25 2005, 07:10:11 PM CET ) Permalink Kommentare [0]