From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: access function parameters with DWARF-less perf probing Date: Wed, 23 Apr 2014 22:21:07 -0700 Message-ID: <87iopzb8vw.fsf@tassilo.jf.intel.com> References: Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mga02.intel.com ([134.134.136.20]:25947 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750721AbaDXFVn (ORCPT ); Thu, 24 Apr 2014 01:21:43 -0400 In-Reply-To: (Jun Wang's message of "Tue, 22 Apr 2014 10:31:34 -0700") Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Jun Wang Cc: linux-perf-users@vger.kernel.org Jun Wang writes: > Hi Everyone, > > With systemTap, in the absence of debugging information (DWARF), one > can access function parameters using (positional) numbers. Can the > same be done with `perf`? > Why? I'm trying to capture variables in a kernel function but I don't > have an good perf with DWARF support and there is are significant > challenges to build one due to the relatively old distro. You can specify the registers according to the ABI. di = 1. arg, si = 2nd arg etc. -Andi -- ak@linux.intel.com -- Speaking for myself only