From owner-freebsd-questions Sat Jul 24 17:17: 8 1999 Delivered-To: freebsd-questions@freebsd.org Received: from avarice.riverstyx.net (hq-port-97.harbour-dhcp-pool.infinetgroup.com [207.23.37.97]) by hub.freebsd.org (Postfix) with ESMTP id 2D62D15216 for ; Sat, 24 Jul 1999 17:17:04 -0700 (PDT) (envelope-from unknown@riverstyx.net) Received: from avarice (unknown@avarice [207.23.37.97]) by avarice.riverstyx.net (8.9.3/8.9.3) with ESMTP id RAA02806; Sat, 24 Jul 1999 17:17:05 -0700 Date: Sat, 24 Jul 1999 17:17:05 -0700 (PDT) From: Tani Hosokawa To: Francisco Reyes Cc: Evren Yurtesen , FreeBSD questions Subject: Re: By default, FreeBSD kernels are not optimized.??? In-Reply-To: <199907250011.UAA21784@arutam.inch.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 24 Jul 1999, Francisco Reyes wrote: > On Sun, 25 Jul 1999 01:22:07 +0300, Evren Yurtesen wrote: > > >what does this text mean exactly, which is referenced from > >http://www.freebsd.org/handbook/internals-vm.html > > > >By default, FreeBSD kernels are not optimized. > > makeoptions DEBUG="-g" > > makeoptions COPTFLAGS="-O2 -pipe" > > That refers to the C compiler optimizations. > There are different levels and types of optimizations that the compiler > can do and by default FreeBSD IS NOT compiled with any of them. Those optimizations aren't guaranteed to produce any performance increases... in fact, with some of the loop unrolling that some of those optimizations will enable, you may even see performance drops in certain programs. I'd be interested in seeing what kind of gains you'd actually get from 3+. Also, some of those higher optimization levels have been known to product instability and buggy code. --- tani hosokawa river styx internet To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message