Date: Tue, 19 Aug 2003 10:22:18 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Dan Nelson <dnelson@allantgroup.com> Cc: freebsd-hackers@freebsd.org Subject: Re: GEOM Gate. Message-ID: <45646.1061281338@critter.freebsd.dk> In-Reply-To: Your message of "Sun, 17 Aug 2003 16:16:27 CDT." <20030817211627.GC2653@dan.emsphone.com>
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In message <20030817211627.GC2653@dan.emsphone.com>, Dan Nelson writes: >I think this just demonstrates that you should not run benchmarks with >all your debugging flags enabled :) Most people will not be running >production systems with WITNESS, and parts of the kernel that bog down >under the heavy load of WITNESS may work just fine on a regular kernal >config. To quote from src/UPDATING: ] NOTE TO PEOPLE WHO THINK THAT 5.0-CURRENT IS SLOW: ] FreeBSD 5.0-CURRENT has many debugging features turned on, in ] both the kernel and userland. These features attempt to detect ] incorrect use of system primitives, and encourage loud failure ] through extra sanity checking and fail stop semantics. They ] also substantially impact system performance. If you want to ] do performance measurement, benchmarking, and optimization, ] you'll want to turn them off. This includes various WITNESS- ] related kernel options, INVARIANTS, malloc debugging flags ] in userland, and various verbose features in the kernel. Many ] developers choose to disable these features on build machines ] to maximize performance. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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