>Number:         25182
>Category:       port-i386
>Synopsis:       bad interrupt latency for com ports on i386 SMP
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 14 11:37:00 UTC 2004
>Closed-Date:
>Last-Modified:
>Originator:     Martin Husemann
>Release:        NetBSD 2.0C
>Organization:
>Environment:
System: NetBSD night-porter.duskware.de 2.0C NetBSD 2.0C (PORTER) #4: Tue Apr 13 14:48:11 CEST 2004 martin@night-porter.duskware.de:/usr/src/sys/arch/i386/compile/PORTER i386
Architecture: i386
Machine: i386
>Description:

On a i386 SMP machine with 

options 	COM_MPLOCK	# com MP locking; REQUIRED on MP i386

I see this kind of messages a lot lately:

Apr 14 12:10:11 night-porter /netbsd: com0: 1 silo overflow, 0 ibuf floods
Apr 14 12:13:48 night-porter /netbsd: com0: 1 silo overflow, 0 ibuf floods
Apr 14 12:14:50 night-porter /netbsd: com0: 1 silo overflow, 0 ibuf floods
Apr 14 12:17:56 night-porter /netbsd: com3: 1 silo overflow, 0 ibuf floods
Apr 14 12:18:58 night-porter /netbsd: com0: 3 silo overflows, 0 ibuf floods
Apr 14 12:23:07 night-porter /netbsd: com0: 2 silo overflows, 0 ibuf floods
Apr 14 12:24:08 night-porter /netbsd: com0: 1 silo overflow, 0 ibuf floods
Apr 14 12:25:10 night-porter /netbsd: com0: 2 silo overflows, 0 ibuf floods
Apr 14 12:27:46 night-porter /netbsd: com0: 2 silo overflows, 0 ibuf floods
Apr 14 12:31:22 night-porter /netbsd: com0: 1 silo overflow, 0 ibuf floods

There are no high-speed serial connections, it's just a few 9600 bps serial
consoles.

>How-To-Repeat:
s/a
>Fix:
n/a
>Release-Note:
>Audit-Trail:
>Unformatted: