Run queue threshold for Ultra SPARC IV CPUs
G'day Support,
From my customer, who is running Solaris 8 (kjp117350-28) :
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Hi,
Could you please help me with the following question.
One of the metrics that we use when estimating whether or not we have enough CPU resources available is the run queue. We often use the following rule of thumb. If the number of processes in the run queue is greater than four times the number of CPUs or thereabouts we look at adding additional CPU resources (Ultra SPARC II or III, single core CPU). This figure is based upon a section in "Sun Performance and Tuning" by Adrian Cockcroft.
When using a dual core processor such as the Ultra SPARC IV CPU does this calculation change? Is it more variable? i.e some people say that a dual core CPU gives around a 25% to 75% boost in performance. Would a run queue threshold based upon number of CPUs multiplied by 4 by 1.5 be adequate. Where 1.5 assumes a 50% performance boost?
Should each core be given equal value when calculating a run queue threshold (rule of thumb)? i.e number CPUs x number of cores?
Thank you.
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...and thank you support,
Regards,
Michael Abboud
Alphawest Services Pty Ltd
