Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763650Ab3IEMpw (ORCPT ); Thu, 5 Sep 2013 08:45:52 -0400 Received: from fw-tnat.cambridge.arm.com ([217.140.96.21]:50845 "EHLO cam-smtp0.cambridge.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759668Ab3IEMpv (ORCPT ); Thu, 5 Sep 2013 08:45:51 -0400 Date: Thu, 5 Sep 2013 13:45:09 +0100 From: Will Deacon To: Jean Pihet Cc: Jiri Olsa , "linux-kernel@vger.kernel.org" , "linaro-kernel@lists.linaro.org" , "linux-arm-kernel@lists.infradead.org" , "patches@linaro.org" , michael.hudson@linaro.org Subject: Re: [PATCH 3/3] perf: parse the .debug_frame section in case .eh_frame is not present Message-ID: <20130905124508.GE9696@mudshark.cambridge.arm.com> References: <1378317854-25965-1-git-send-email-jean.pihet@linaro.org> <1378317854-25965-4-git-send-email-jean.pihet@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1378317854-25965-4-git-send-email-jean.pihet@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 54 Hi Jean, [adding Michael, since I know he was interested in this] On Wed, Sep 04, 2013 at 07:04:14PM +0100, Jean Pihet wrote: > On ARM the debug info is not present in the .eh_frame sections but > instead in .debug_frame. > Use libunwind to load and parse the debug info. How have you tested this? Regardless of whether or not I apply this patch, I get the same (broken/truncated) callchains for userspace in perf report. E.g. the following stupid program (built with -O0 -g): --->8 void bar(void) { int i; for (i = 0; i < 1000000; ++i) asm volatile("nop" ::: "memory"); } void foo(void) { bar(); } int main(void) { foo(); return 0; } 8<--- Gives me an incomplete callchain: # Overhead Command Shared Object Symbol # ........ ........ ................. ............................... # 0.00% unwindme unwindme [.] bar | --- bar This is the same with or without your patch. Will -- 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/