From owner-freebsd-current Fri Dec 1 13:35:05 1995 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id NAA26077 for current-outgoing; Fri, 1 Dec 1995 13:35:05 -0800 Received: from halloran-eldar.lcs.mit.edu (halloran-eldar.lcs.mit.edu [18.26.0.159]) by freefall.freebsd.org (8.6.12/8.6.6) with SMTP id NAA26054 for ; Fri, 1 Dec 1995 13:34:51 -0800 Received: by halloran-eldar.lcs.mit.edu; (5.65/1.1.8.2/19Aug95-0530PM) id AA13642; Fri, 1 Dec 1995 16:21:39 -0500 Date: Fri, 1 Dec 1995 16:21:39 -0500 From: "Garrett A. Wollman" Message-Id: <9512012121.AA13642@halloran-eldar.lcs.mit.edu> To: "Marc G. Fournier" Cc: current@freebsd.org Subject: -O6/-fstrength-reduce for kernel (Was: Re: changes in -current...) In-Reply-To: References: <199512011252.XAA17404@godzilla.zeta.org.au> Sender: owner-current@freebsd.org Precedence: bulk < said: > Also, someone mentioned using -fno-strength-reduce? If I > used that, with -O6, would I notice any benefits, or does using > -fno-strength-reduce just about take out any benefits to -O6? Your Mileage May Vary. In the testing I was doing last month on packet send and forwarding rates, I found that using any sort of optimization beyond the default `-O' resulted in a repeatable 1-3% /decrease/ in maximum packet rate. The same was true of `-m486'. I'll be interested to see the results if the Pentium enhancements are ever integrated into the main gcc line. I suspect there may be some funny cache effects going on, but it's next to impossible to tell. -GAWollman -- Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... wollman@lcs.mit.edu | Shashish is the bonding of hearts in spite of distance. Opinions not those of| It is a bond more powerful than absence. We like people MIT, LCS, ANA, or NSA| who like Shashish. - Claude McKenzie + Florent Vollant