Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 17 Dec 2002 12:39:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 17 Dec 2002 12:39:16 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:60173 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Tue, 17 Dec 2002 12:39:15 -0500 Date: Tue, 17 Dec 2002 09:47:39 -0800 (PST) From: Linus Torvalds To: "Richard B. Johnson" cc: Hugh Dickins , Dave Jones , Ingo Molnar , Ulrich Drepper , , Subject: Re: Intel P6 vs P7 system call performance In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 738 Lines: 25 On Tue, 17 Dec 2002, Richard B. Johnson wrote: > On Mon, 16 Dec 2002, Linus Torvalds wrote: > > > > instruction for a system call just do a > > > > call 0xfffff000 > > So you are going to do a system-call off a trap instead of an interrupt. No no. The kernel maps a magic read-only page at 0xfffff000, and there's no trap involved. The code at that address is kernel-generated for the CPU in question, and it will do whatever is most convenient. No traps. They're slow as hell. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/