On 2/3/2014 8:30 AM, Blaicher, Christopher Y. wrote:
IBM, with V2.1, has added instruction counts to the type 30 SMF records. These
counts are done when HIS is active on the processors for the LPAR. I do not
know how they are doing it, but a reasonable guess is they are using the new
instructions to get the current counts from the hardware each time a context
switch is done. I can only hope they do it for EVERY context switch and as
close to the switch as possible, which is what QCM did to improve SMF timings.
I have not been able to run against a V2.1 system yet, but I am hoping that for
the exact same work I will see about the same instruction counts, even though
the reported CPU time might vary significantly based on how busy a machine is.
Hopefully, they are not counting time spent resolving page faults and
such that _validly_ belong in "uncaptured" time today.
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
http://www.phoenixsoftware.com/
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