From owner-freebsd-hackers Sun Mar 10 5: 3:19 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mailsrv.otenet.gr (mailsrv.otenet.gr [195.170.0.5]) by hub.freebsd.org (Postfix) with ESMTP id 959FC37B402 for ; Sun, 10 Mar 2002 05:03:15 -0800 (PST) Received: from hades.hell.gr (patr530-a138.otenet.gr [212.205.215.138]) by mailsrv.otenet.gr (8.12.2/8.12.2) with ESMTP id g2AD30ft024576; Sun, 10 Mar 2002 15:03:03 +0200 (EET) Received: from hades.hell.gr (hades [127.0.0.1]) by hades.hell.gr (8.12.2/8.12.2) with ESMTP id g2AD309m003233; Sun, 10 Mar 2002 15:03:00 +0200 (EET) (envelope-from keramida@freebsd.org) Received: (from charon@localhost) by hades.hell.gr (8.12.2/8.12.2/Submit) id g2ACpwBR002733; Sun, 10 Mar 2002 14:51:58 +0200 (EET) (envelope-from keramida@freebsd.org) X-Authentication-Warning: hades.hell.gr: charon set sender to keramida@freebsd.org using -f Date: Sun, 10 Mar 2002 14:51:58 +0200 From: Giorgos Keramidas To: "Simon 'corecode' Schubert" Cc: freebsd-hackers@freebsd.org Subject: Re: Swapping performance Message-ID: <20020310125158.GA798@hades.hell.gr> References: <20020307090707.GC26621@elvis.mu.org> <20020307142759.0d95d467.mitko@rila.bg> <20020307080906.367be8df.gclarkii@vsservices.com> <20020307164724.D377@straylight.oblivion.bg> <20020307153615.GB1942@student.uu.se> <20020307164500.5dd21d16.corecode@corecode.ath.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020307164500.5dd21d16.corecode@corecode.ath.cx> User-Agent: Mutt/1.3.27i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 2002-03-07 16:45, Simon 'corecode' Schubert wrote: > to everybody who doesn't believe that: it really generates bad code. > i've been having severe problems with my tcp and udp stack lately (on a > i586/mmx machine). guess what, -O2 resulted in code which >>sometimes<< > generated bad tcp and/or udp checksums (depending on ip). i didn't > investigate any further, but believe me: not being able to access some > dns servers is a pain in the ass. I've seen this too. When I built both my kernel and userland with -O3, problems accessing the Internet started. When I tried to use tcpdump to find out what went wrong, I saw that it reported *all* outgoing packets for *some* hosts as invalid [0xffff]. The funny thing was that depending on which source/destination I used, it would either work or fail. For destinations that it failed once, it failed all the time. Since I could not verify both the userland and kernel binaries, I chose to disable most optimizations and stick with -O :-) Giorgos Keramidas FreeBSD Documentation Project keramida@{freebsd.org,ceid.upatras.gr} http://www.FreeBSD.org/docproj/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message