Hello,
I am working on version
Adaptive Server Enterprise/16.0 SP02 PL05 HF1/EBF 26759 SMP/P/x86_64/Enterprise Linux/ase160sp02pl05x/2736/64-bit/FBO/Mon Jan 16 23:55:31 2017
I have been hitting high CPU runs, inspecting mon* tables does not show any blocking and also, most of the time the CPU was hitting 90%+ usage. I plan to increase the number of CPU from 48VCPU to 64VCPU. Previously the syb_Default_pool was configured to 46 and then reduced to 32 to ensure we are not over hitting the parallel contention. However, after careful observation, i plan to increase to 64VVCPU, answer i am trying to find is what is a good configuration, should i configure same number of syb_default_pool thread as number of CPU or use any know practice default thumb rule. Usually safe is to assign 80% of capacity. Can you someone please suggest what should be the new configuration for syb_default_pool
Best Regards,
- Imran.
Rule of thumb
In case this is a standalone dbhost - and assuming you do not have an named thread pools in ASE:
thread count in syb_default_pool = #physical cores - 2
That leaves some space for OS and other ASE thread activity in syb_blocking_pool and syb_system_pool.
In any case I strongly discourage configuring online engines higher than # physical cores. That bears a very high risk of spinlock contention.
HTH
Tilman
Also, if database dumps are being run with multiple stripes and compression, each stripe will eat up some CPU doing compression ("sybmultbuf" processes). I see 60-90% CPU per dump stripe using the "with compression=100" option on Linux.
So you need to leave enough spare CPU so dumps don't bottleneck the machine.