From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752956AbbESQwL (ORCPT ); Tue, 19 May 2015 12:52:11 -0400 Received: from foss.arm.com ([217.140.101.70]:35442 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756319AbbESQwH (ORCPT ); Tue, 19 May 2015 12:52:07 -0400 Date: Tue, 19 May 2015 17:52:03 +0100 From: Catalin Marinas To: Hou Pengyang Cc: will.deacon@arm.com, wangnan0@huawei.com, a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, acme@kernel.org, mingo@redhat.com, paulus@samba.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v5] arm64: perf: Fix callchain parse error with kernel tracepoint events Message-ID: <20150519165202.GA21251@e104818-lin.cambridge.arm.com> References: <20150508153758.GG25587@arm.com> <1431256060-161483-1-git-send-email-houpengyang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431256060-161483-1-git-send-email-houpengyang@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 10, 2015 at 11:07:40AM +0000, Hou Pengyang wrote: > For ARM64, when tracing with tracepoint events, the IP and pstate are set > to 0, preventing the perf code parsing the callchain and resolving the > symbols correctly. > > ./perf record -e sched:sched_switch -g --call-graph dwarf ls > [ perf record: Captured and wrote 0.146 MB perf.data ] > ./perf report -f > Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194 > Children Self Command Shared Object Symbol > 100.00% 100.00% ls [unknown] [.] 0000000000000000 > > The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills > several necessary registers used for callchain unwinding, including pc,sp, > fp and spsr . > > With this patch, callchain can be parsed correctly as follows: > > ...... > + 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink > + 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down > + 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get > + 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33 > - 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify > pfkey_send_policy_notify > pfkey_get > v9fs_vfs_rename > page_follow_link_light > link_path_walk > el0_svc_naked > ....... > > Signed-off-by: Hou Pengyang > Acked-by: Will Deacon Queued for 4.2. Thanks. -- Catalin