Kernel tuning - round_robin & Shed_min_idle

[Alexey Borchev]

I've got ES45, 4x1GHz, 16MB RAM, Tru64 5.1A PK3, Oracle 8.1.7.4, Sql client app called Concorde(By Damgaard -> Navision -> MicroSoft).

System load is CPU-intensive - IO bandwith looks enough.
Lots of small&simple SQL between Oracle and Concorde.

In the:
> man sys_attrs_proc
I've found 2 interesting parameters -
round_robin_switch_rate and sched_min_idle
[man quoting is skipped...]

1) What is CPU overhead on context switching?
2) When task (Oracle's dedicated process or SQL client) done it's job and sent query/reply to it's peer - the rest of timeslice is used or wasted? (Or, can I allocate BIG timeslice).
3) Can I obtain CPU cache hit rate?
4) Did someone played with this parameters, if there is any effect?

And, more:
5) Memory can be non- 2-way, 4-way interleaved.
Did anyone noticed performance difference?
6) Does Oracle 8.1.7 work on Marvel - ES80, ES1280? Anyone tryed?
7) Is XMesh utility included into Tru64 5.1B?
8) Does XMesh utility operate on Alpha ev6 systems?

[Stephen Carpenter]

1) What is CPU overhead on context switching?

A context switch is not overhead its is necessary because either the current thread is done with the CPU for now or another thread needs the CPU more. If a thread finishes its time quantum and there is nothing else waiting to run then the scheduler will let the thread run for another quantum, no contect switch will take place.

2) When task (Oracle's dedicated process or SQL client) done it's job and sent query/reply to it's peer - the rest of timeslice is used or wasted?

The unused quantum is given to another thread.

3) Can I obtain CPU cache hit rate?

No.

4) Did someone played with this parameters, if there is any effect?

The amount of benefit depends on the app and the loading of the system. Only a real life test can determine if it will work for you.

5) Memory can be non- 2-way, 4-way interleaved.
Did anyone noticed performance difference?

Depends on the app. It can be very important if the app is memory intensive.

6) Does Oracle 8.1.7 work on Marvel - ES80, ES1280? Anyone tryed?

Yes.

7) Is XMesh utility included into Tru64 5.1B?

Yes.

8) Does XMesh utility operate on Alpha ev6 systems?

No.