Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 2 Aug 2002 07:56:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 2 Aug 2002 07:56:50 -0400 Received: from faui02.informatik.uni-erlangen.de ([131.188.30.102]:2729 "EHLO faui02.informatik.uni-erlangen.de") by vger.kernel.org with ESMTP id ; Fri, 2 Aug 2002 07:56:48 -0400 Date: Fri, 2 Aug 2002 13:34:44 +0200 From: Richard Zidlicky To: Jeff Dike Cc: Alan Cox , linux-kernel@vger.kernel.org Subject: Re: Accelerating user mode linux Message-ID: <20020802133444.E1948@linux-m68k.org> References: <200208012016.g71KGwK27981@devserv.devel.redhat.com> <200208020440.XAA04793@ccure.karaya.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200208020440.XAA04793@ccure.karaya.com>; from jdike@karaya.com on Thu, Aug 01, 2002 at 11:40:28PM -0500 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 876 Lines: 22 On Thu, Aug 01, 2002 at 11:40:28PM -0500, Jeff Dike wrote: > > Your objection to returning through sigreturn was performance. Is performance > a veto of adding an mm switch to sigreturn, or it is possible to make it > acceptible? I have once ported Basilisk to work native on linux-m68k. It works *slow* so I looked what the problem is - the signal delivery in Linux is exorbitantly slow. Eg an SIGILL delivery costs ~ 1650 cycles on a 68060, compared to that sigreturn and getpid are 200-250 and sched_yield with context switch around 400. So sigreturn is not the place I would be looking for the biggest speedups. Richard - 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/