Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265080AbTFCQSB (ORCPT ); Tue, 3 Jun 2003 12:18:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265082AbTFCQSB (ORCPT ); Tue, 3 Jun 2003 12:18:01 -0400 Received: from nat-pool-rdu.redhat.com ([66.187.233.200]:41265 "EHLO devserv.devel.redhat.com") by vger.kernel.org with ESMTP id S265080AbTFCQR7 (ORCPT ); Tue, 3 Jun 2003 12:17:59 -0400 Date: Tue, 3 Jun 2003 12:31:24 -0400 From: Pete Zaitcev To: Martin Schwidefsky Cc: Pete Zaitcev , linux-kernel@vger.kernel.org Subject: Re: sys_lookup_dcookie on s390 Message-ID: <20030603123124.A10799@devserv.devel.redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from schwidefsky@de.ibm.com on Tue, Jun 03, 2003 at 11:22:32AM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1415 Lines: 32 > From: "Martin Schwidefsky" > Date: Tue, 3 Jun 2003 11:22:32 +0200 > > Are you going to assign a number for lookup_dcookie? If yes, when? > > You can use 110 for lookup_dcookie (reusing i386 specific iopl number that > have always been unused for s390). Never came around porting the oprofile > stuff to s390. Do you plan to do it ? I am going to use it with timer profiling at first. It is essentially zero effort port, just add the syscall and config.in entry. Still, do you have a suggestion for any other interrupt? For instance, on i386 it can use NMI. It is my understanding (perhaps incorrect), that using other interrupt can a) increase precision, if HZ is low, but other interrupt can fire more often, b) reduce overhead. Also, sometimes you can do tricks, if hardware allows it. On sparc, for instance, you can redefine __local_cli() in such a way that all interrupts would be closed except the profiling interrupt. Then, the profiler gathers data about people sitting on spinlocks, etc. This is what I am looking for, but I'm not sufficiently versed in the architecture for decide if we have a suitable interrupt source. -- Pete - 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/