Any interest in swat enhancement

David Collier-Brown David.Collier-Brown at
Wed Sep 6 12:22:26 GMT 2000

Jean Francois Micouleau wrote:
> yes ! I would be able to send printer notify updates to all smbd process
> in one shoot :-)
> How do you remove from the queue a message that was send to all the
> smbd process ?

	You either duplicate the messages on send, or keep
	a reference count.  

	One of my smarter colleagues looked at a customer
	system which did the reference-counting, and found
	the locks required were a significant bottleneck
	at high message rates. Implementing send-multiple
	the simple was was a cure.

	This is a general case of what we've found when
	re-implementing System V message queues (several
	times!) over the years: getting the locking right
	is the major performance issue. Other probable
	truisms: many small queues make light work, and
	lock-free (non-circular) queue schemes are cool.

--dave (wearing his Solaris hat) c-b
David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | and astonish the rest.        -- Mark Twain
Willowdale, Ontario   | //
Work: (905) 415-2849 Home: (416) 223-8968 Email: davecb at

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