Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!hub.ucsb.edu!peach!mcm
From: mcm@peach.ucsb.edu (Marcelo C. Mourier)
Newsgroups: comp.os.minix
Subject: Alarm handling in 1.5
Message-ID: <5544@hub.ucsb.edu>
Date: 30 May 90 08:38:20 GMT
Sender: news@hub.ucsb.edu
Reply-To: mcm@peach.ucsb.edu (Marcelo C. Mourier)
Followup-To: mcm@cs.ucsb.edu
Organization: University of California, Santa Barbara
Lines: 14


	When clock_handler() finds out that an alarm has set off it issues an
interrupt(CLOCK) to wake up the clock task. The clock task calls do_clocktick()
to do the processing, which consists in scanning the entire proc table looking
for a non-null p_alarm entry that is less than or equal to realtime. 

	For speed's sake, wouldn't it be better if the alarms were kept in a 
linked list?  This could be easily done by adding a new entry, p_nextalarm, to 
the proc structure that would keep the link between the proc table entries of 
the processes/tasks with pending alarms.  In this way, finding the process/task
to be awekened would require constant time, instead of O(n).

	
Marcelo - mcm@cs.ucsb.edu