From owner-freebsd-arch Sat Feb 8 23:57: 7 2003 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A44AD37B401 for ; Sat, 8 Feb 2003 23:57:06 -0800 (PST) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.FreeBSD.org (Postfix) with ESMTP id 58D3043FA3 for ; Sat, 8 Feb 2003 23:57:06 -0800 (PST) (envelope-from bright@elvis.mu.org) Received: by elvis.mu.org (Postfix, from userid 1192) id 1F771AE162; Sat, 8 Feb 2003 23:57:06 -0800 (PST) Date: Sat, 8 Feb 2003 23:57:06 -0800 From: Alfred Perlstein To: Peter Wemm Cc: Jake Burkholder , Jeff Roberson , arch@FreeBSD.ORG Subject: Re: New kernel allocation API Message-ID: <20030209075706.GO88781@elvis.mu.org> References: <20030207234049.A32864@locore.ca> <20030209074604.EC6962A8B4@canning.wemm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030209074604.EC6962A8B4@canning.wemm.org> User-Agent: Mutt/1.4i Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * Peter Wemm [030208 23:46] wrote: > > And there is hardware support for direct mapping on alpha as well, so it > completely bypasses the TLB entirely for significant benefits. For x86-64 > there'll likely be up to 2^39 of direct mapped space as well, but using 2MB > pages (use an entire level 4 directory slot for direct mapping to avoid the > APTD evilness). We just dont have the space to do this on plain x86 :-(. It seems to me that someone should run some tests to get numbers to determine if the tlb optimization helps more than the kmem-array optimization. However the problem with that is that much more of the kernel should be converted to use zones/slabs before counting on the data gathered. I'm trusting you guys that avoiding the tlb shootdowns help quite a bit, but then again the cost of each free(9) seems quite high. I may see if I can convert some paths in the kernel to use zones. :) -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message