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Jun 22, 2016 at 10:53 AM

ASE on Power8 / 16 Cpus + SMT8 ( 128 Vcpus)



I'm performing perfromance testing with ASE 15.7 / SP134 on AIX Power8. The machine has 16 Cores and SMT 8 is activated

ASE is configured with 'only' 64 'engines' (ie the thread pool syb_default_pool has 64 Threads) and aggressive tasks stealing is on.

The Idle Time out has been set to 2000.

When ASE activity reach 65%/70% the the spinlock contention on 'Sched Q' and 'Global Sched' reach respectively 52% and 50 %.

When agressive task stealing is Off the others spinlocks do not exceed 5%, so the real issue seems to be the spinlocks on 'Sched Q' and 'Global Sched'

My questions are :

-What is part of this rate of spinlock activity on overall Engine % Usage ? Is there any way to determine it or evaluate it ?

-What is maximum of 'Engine' (ie threads in syb_default_pool) we can have without having Sched Spinlock issue ?

-Will it behave differently with v16 ?