From owner-freebsd-current  Wed Mar  8 10:29:46 2000
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From: Mohit Aron <aron@cs.rice.edu>
Message-Id: <200003081829.MAA14589@cs.rice.edu>
Subject: enabling APIC without SMP
To: freebsd-current@freebsd.org, freebsd-hackers@freebsd.org
Date: Wed, 8 Mar 2000 12:29:35 -0600 (CST)
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Hi,
	I'm using a FreeBSD-current snapshot from 3rd January 2000. It seems
that in order to enable APICs (option APIC_IO in kernel configuration file),
one needs to also compile the kernel with SMP support (option SMP in kernel
configuration file). While enabling the APIC is desirable even on a 
uniprocessor (provides more IRQs, interrupt ovhd becomes less, provides
on-chip timer), enabling SMP support on a uniprocessor brings down the 
performance (I've noticed a degradation of 22% in performance of a webserver
when a kernel was compiled with SMP support than without). Would it be possible
to allow enabling the APIC without requiring support for SMP in future
versions of FreeBSD ?

Since I'm using a snapshot that's about two months old, I apologize if the
above has already been addressed in the latest snapshots.



- Mohit


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