Date: Mon, 15 Jan 2001 14:25:44 -0700 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: John Baldwin <jhb@FreeBSD.org> Cc: Peter Wemm <peter@netplex.com.au>, Poul-Henning Kamp <phk@critter.freebsd.dk>, Wilko Bulte <wkb@freebie.demon.nl>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Bruce Evans <bde@zeta.org.au> Subject: Re: cvs commit: src/sys/i386/conf GENERIC Message-ID: <200101152125.f0FLPis60113@aslan.scsiguy.com> In-Reply-To: Your message of "Mon, 15 Jan 2001 13:17:21 PST." <XFMail.010115131721.jhb@FreeBSD.org>
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>See those 'cli' and 'popfl' instrucitons? Those are _privileged_. Userland >can't disable/enable interrupts, so we have to trap into the kernel to do this >no matter what. All that is required in the userland implementation is the setting of a flag so the userland thread scheduler does not perform a thread switch. Having an interrupt fire does not have the same consequences on a userland program as it does for the kernel. >If you want to patch the code to do a syscall instead of a >cmpxchg instruction, fine. However, emulating atomic_cmpset in userland on a >386 requires a trap into the kernel. Please assume for at least 1 minute that >the SMPng guys are not complete bumbling idiots and that we may have actually >thought about this for at least 5 minutes. I don't think your idiots at all, I just think that you are interested in making a case of deprecation of the i386 because it is the quickist path from A->B. If we decide to deprecate the i386 on technical ground, so be it, but I haven't seen such a case presented yet. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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