From owner-freebsd-smp Tue Feb 26 14:21:58 2002 Delivered-To: freebsd-smp@freebsd.org Received: from mail.rpi.edu (mail.rpi.edu [128.113.22.40]) by hub.freebsd.org (Postfix) with ESMTP id 21F6737B402 for ; Tue, 26 Feb 2002 14:21:54 -0800 (PST) Received: from [128.113.24.47] (gilead.acs.rpi.edu [128.113.24.47]) by mail.rpi.edu (8.12.1/8.12.1) with ESMTP id g1QMLqdq131454; Tue, 26 Feb 2002 17:21:52 -0500 Mime-Version: 1.0 X-Sender: drosih@mail.rpi.edu Message-Id: In-Reply-To: <1014754359.231.77.camel@NewStorm.WhiteBarn.Com> References: <1014749196.231.48.camel@NewStorm.WhiteBarn.Com> <1014754359.231.77.camel@NewStorm.WhiteBarn.Com> Date: Tue, 26 Feb 2002 17:21:51 -0500 To: Bob Van Valzah From: Garance A Drosihn Subject: Re: Performance vs. Stable Cc: smp@FreeBSD.ORG Content-Type: text/plain; charset="us-ascii" ; format="flowed" X-Scanned-By: MIMEDefang 2.3 (www dot roaringpenguin dot com slash mimedefang) Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org At 2:12 PM -0600 2/26/02, Bob Van Valzah wrote: >Yes, good point, sorry. I shouldn't've glossed over that. > >The short answer is that I used GENERIC kernels with as few changes >as possible. So on -CURRENT, the kernel I tested with was running >INVARIANTS, INVARIANT_SUPPORT, WITNESS, and WITNESS_SKIPSPIN. These >were not set on my test -STABLE kernel since they're not set in >GENERIC there. The thing is, -STABLE doesn't need all the extra sanity-checking code, so it is not compiled in. But with all the wide-ranging changes going on in -CURRENT, it is much more important to have the extra checking. >If these settings are causing large differences in timings, I think >it'll show up when I compare kgmon/gprof results between kernels. I >can also just compile a kernel without these settings and see how it >differs. You will find that these settings make a huge difference in the timings of many things. >I'm still very new to this so I'm trying to map the benchmarking >space and see where there are interesting questions. You've opened >my eyes to an area I'd missed but should've seen. Are there others? Probably, but I don't know enough to say what they are... :-) -- Garance Alistair Drosehn = gad@eclipse.acs.rpi.edu Senior Systems Programmer or gad@freebsd.org Rensselaer Polytechnic Institute or drosih@rpi.edu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message