From owner-freebsd-smp Tue Feb 26 16:28:44 2002 Delivered-To: freebsd-smp@freebsd.org Received: from sherryl.salk.edu (sherryl.salk.edu [198.202.70.151]) by hub.freebsd.org (Postfix) with ESMTP id 6C9BE37B405 for ; Tue, 26 Feb 2002 16:28:32 -0800 (PST) Received: from merckx.salk.edu (merckx.salk.edu [198.202.70.90]) by sherryl.salk.edu (8.12.1/8.12.1) with ESMTP id g1R0SU7h070998; Tue, 26 Feb 2002 16:28:30 -0800 (PST) Date: Tue, 26 Feb 2002 16:27:51 -0800 (PST) From: Jorge Aldana To: Garance A Drosihn Cc: Bob Van Valzah , Subject: Re: Performance vs. Stable In-Reply-To: Message-ID: <20020226162616.E32126-100000@merckx.salk.edu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 Why isn't WITNESS and WITNESS_SKIPSPIN in LINT? Or is it undocumented? While I'm at it what are they, if you know. Jorge On Tue, 26 Feb 2002, Garance A Drosihn wrote: > 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 > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message