Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756189Ab2BGD4Q (ORCPT ); Mon, 6 Feb 2012 22:56:16 -0500 Received: from ozlabs.org ([203.10.76.45]:51632 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755828Ab2BGD4P (ORCPT ); Mon, 6 Feb 2012 22:56:15 -0500 Date: Tue, 7 Feb 2012 14:55:35 +1100 From: Anton Blanchard To: Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , Frederic Weisbecker , emunson@mgebm.net, imunsie@au1.ibm.com, eranian@google.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH] perf annotate: Numeric assembly labels cause incorrect annotation Message-ID: <20120207145535.71b9f22d@kryten> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.24.4; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2696 Lines: 73 A perf annotate of a kernel function written in assembly shows very strange percentages: : _GLOBAL(__copy_tofrom_user_base) ... : addi r3,r3,1 99.67 : c00000000004d78c: addi r3,r3,1 : 0.00 : 1: bf cr7*4+2,2f 0.07 : c00000000004d790: bne- cr7,c00000000004d7a4 : err1; lhz r0,0(r4) 0.00 : c00000000004d794: lhz r0,0(r4) : addi r4,r4,2 0.00 : c00000000004d798: addi r4,r4,2 : err1; sth r0,0(r3) 0.00 : c00000000004d79c: sth r0,0(r3) : addi r3,r3,2 99.60 : c00000000004d7a0: addi r3,r3,2 : 0.00 : 2: bf cr7*4+1,3f 0.12 : c00000000004d7a4: ble- cr7,c00000000004d7b8 : err1; lwz r0,0(r4) 0.00 : c00000000004d7a8: lwz r0,0(r4) : addi r4,r4,4 0.00 : c00000000004d7ac: addi r4,r4,4 : err1; stw r0,0(r3) 0.00 : c00000000004d7b0: stw r0,0(r3) : addi r3,r3,4 99.48 : c00000000004d7b4: addi r3,r3,4 ~300% in one function. Urgh. This is caused by the way we parse objdump -S output, eg: addi r3,r3,1 c00000000004d78c: addi r3,r3,1 1: bf cr7*4+2,2f c00000000004d790: bne- cr7,c00000000004d7a4 We assume the asm label (1:) is an address, compute a bogus offset into the function and then screw up the matching of samples to lines. I notice this also fails with c inline assembly in a similar manner. We already have a sanity check that the address is not beyond the end of the function, so add a check against the start too. Signed-off-by: Anton Blanchard --- Cc: Index: linux-tip/tools/perf/util/annotate.c =================================================================== --- linux-tip.orig/tools/perf/util/annotate.c 2012-01-09 17:45:09.056373433 +1100 +++ linux-tip/tools/perf/util/annotate.c 2012-02-07 13:53:01.610970209 +1100 @@ -244,7 +244,7 @@ static int symbol__parse_objdump_line(st end = map__rip_2objdump(map, sym->end); offset = line_ip - start; - if (offset < 0 || (u64)line_ip > end) + if (offset < 0 || (u64)line_ip < start || (u64)line_ip > end) offset = -1; } -- 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/