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Conference noted::hackers_v1

Title:	-={ H A C K E R S }=-
Notice:	Write locked - see NOTED::HACKERS
Moderator:	DIEHRD::MORRIS

Created:	Thu Feb 20 1986
Last Modified:	Mon Aug 03 1992
Last Successful Update:	Fri Jun 06 1997
Number of topics:	680
Total number of notes:	5456

571.0. "monitor interrupt stack" by THESUN::PLANK () Tue Oct 06 1987 12:12

    This is not quite the right conference for this query, but every
    time I try and access VAX_VMS_BEGINNERS I get an error. This conference
    is so full of VMS that I'm sure someone will know the answer.
    
    The question is: how much time should an idle system be spending
    on the interrupt stack; how is this information retrieved from the
    sys by the monitor modes command and is 25% excessive, any thoughts
    on the cause.
    
    
    Steve.

T.R	Title	User	Personal Name	Date	Lines
571.1	It depends.	CHOVAX::YOUNG	Back from the Shadows Again,	`Tue Oct 06 1987 13:07`	10
	The answer is that it all depends. Normally I would say that 25% Interrupt time is excessive. However it depends on what type of VAX, is it in a cluster(what kind), what special hardware exists, how is the system being used, and what are the other CPU numbers like. If you can answer these questions then I (or someone else) could probably give you a more specific answer. -- Barry
571.2	SPM's PCsampler	ATPS::MALLORY	SPM V3.2 or bust...	`Tue Oct 06 1987 19:58`	7
	Try using our PCsampler. It can tell you by module in the exec where u're spendin your interrupt stack time. Kevin VAX SPM Development (Kit available on HITECH::SYS$PUBLIC:SPM031_SDC.A,.B )
571.3		PSW::WINALSKI	Paul S. Winalski	`Fri Oct 09 1987 14:35`	13
	An idle VMS system should spend next to zero time on the interrupt stack. The only interrupt stack activity on an idle system is the timer going off every 20ms (or whatever the quantum interval is). If you are spending 25% on the I-stack, your system is not idle. Possible explanations: - your system is part of a VAXcluster that is doing things behind your back - your system is on an ethernet and has service enabled, and there are things elsewhere on the ethernet trying to boot - your system is a level 1 or level 2 DECnet router --PSW
571.4	Oops, I missed the "idle system" comment.	CHOVAX::YOUNG	Back from the Shadows Again,	`Fri Oct 09 1987 16:39`	1

571.5		NEWVAX::CRITZ	In one damn minute, Captain	`Fri Oct 09 1987 17:18`	3
	Addendum to the list .3 - You're running VAX PSI (at least one of the older versions).
571.6		MONSTR::FRAZIER	James Frazier VMS/VAXclusters-CSSE	`Mon Oct 12 1987 10:08`	6
	Do you have any comm gear? Like DHs, DZs ? If a comm line is 'bad' or hooked to a 'bad' modem, the can spend a lot of time handeling the spurious interrupts.