Date: Tue, 26 Feb 2002 17:21:51 -0500 From: Garance A Drosihn <drosih@rpi.edu> To: Bob Van Valzah <Bob@Talarian.Com> Cc: smp@FreeBSD.ORG Subject: Re: Performance vs. Stable Message-ID: <p0510140db8a1ba41ee62@[128.113.24.47]> In-Reply-To: <1014754359.231.77.camel@NewStorm.WhiteBarn.Com> References: <1014749196.231.48.camel@NewStorm.WhiteBarn.Com> <p05101403b8a193a7e251@[128.113.24.47]> <1014754359.231.77.camel@NewStorm.WhiteBarn.Com>
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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
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