SMP on FreeBSD 6.x and 7.0: Worth doing?

[Bill Vermillion]

It's Tue, Dec 25, 2007 at 12:00 . I'm in a small dim room with
doors labeled "Dungeon" and "Forbidden". There is noise, the door
marked Dungeon flies open and freebsd-stable-request at freebsd.org SHOUTS:

> Date: Mon, 24 Dec 2007 08:49:36 -0700
> From: Brett Glass <brett at lariat.net>
> Subject: Re: SMP on FreeBSD 6.x and 7.0: Worth doing?
> To: Scott Long <scottl at samsco.org>
> Cc: stable at freebsd.org

> At 07:14 AM 12/24/2007, Scott Long wrote:

> >Brett,

> >There could be several problems here:

> >1. WITNESS, INVARIANTS, malloc debugging. Are any of these
> >turned on for you? I don't recall if malloc debugging got
> >turned off yet for the 7.0 snapshots.

> I nuked debugging when I recompiled the kernel with SCHED_ULE.

> >2. Disk subsystem. What kind of disk controller are you using?
> >Not all drivers work well in FreeBSD. Are linux and freebsd
> >using identical hardware?

> They were. The drives are SATA.

That still doesn't tell us if the drives are identical in 
throughput.

Unless the drives are the same model/manufacturer, you should
go to the manufacturers web-site for both drives, and look for 
the technical specs.  THen you need to look for the speed of 
data transfer from the platter to the internal memory.

I've seen [ in the past ] drives with lower revolutions per minute
out-perform faster rotating drives because the slower drive had
a better head design and could transfer data much faster.

If this task is not up to you perhaps you could post the
make/model number of the drives on both systems.   Without knowing
the sub-system capability you could be misleading yourself
with other tests.

Bill
-- 
Bill Vermillion - bv @ wjv . com