Threaded mode SAP ASE 16 and Linux Hyper/Multi threaded cpus(cores)

[jmtorres]

Good Day, 

Reading sap kba 2450359 - 'How to configure number of thread when using threaded kernel mode? - ASE ,

it's content mentions:

'For an ASE using 'threaded' kernel mode, the recommendation is for the number of threads
to be configured as follows: Number of Threads = (Number of CPUs - 2).

For example: 16 CPUs on the host, the number of thread should be set to 14.'

This example assumes a 1-1 relationship , i.e, 1 core  spans 1 OS thread?

So if we have the same 16 cores(cpus) in which each core spans 2 threads, then we'll have 32 logical processors. In this case syb_default_pool should tune to 30?

Thank you

[sladebe]

I don't have the "how many ASE threads" to configure answer, but I thought I'd mention a few other things. H/W core threading is aimed for improving concurrency in a multi-user environment. Doesn't apply so much in a dedicated database environment.   In my environment, we turn off H/W core threads.

If you have a bunch of physical cores, you might have to worry about NUMA (non uniform memory architecture)  .  This is where groups of cores are assigned they're own local bank of memory.   Memory updates that don't hit the local bank go across the global bus to the destination memory bank.   ASE is not NUMA aware.  Ie., it doesn't try and keep an ASE level threads assigned to a physical group of cores.   Some places just go with 4 or 8 memory regions/banks.   Some sites just go with 1 memory region (all updates automatically get all memory banks).  I can't find anyway command to bind a thread pool to a set of CPUs/cores (see "create thread pool").  The old CPU-to-engine binding commands no longer work in threaded mode (feel free to correct me if I'm wrong)