From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753454AbcEMSBL (ORCPT ); Fri, 13 May 2016 14:01:11 -0400 Received: from mail.kernel.org ([198.145.29.136]:49015 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312AbcEMSBJ (ORCPT ); Fri, 13 May 2016 14:01:09 -0400 Date: Fri, 13 May 2016 15:01:04 -0300 From: Arnaldo Carvalho de Melo To: David Ahern Cc: Hekuang , Arnaldo Carvalho de Melo , peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, wangnan0@huawei.com, jpoimboe@redhat.com, ak@linux.intel.com, eranian@google.com, namhyung@kernel.org, adrian.hunter@intel.com, sukadev@linux.vnet.ibm.com, masami.hiramatsu.pt@hitachi.com, tumanova@linux.vnet.ibm.com, kan.liang@intel.com, penberg@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/7] perf tools: Remove the logical that skip buildid cache if symfs is given Message-ID: <20160513180104.GL11346@kernel.org> References: <1463042596-61703-1-git-send-email-hekuang@huawei.com> <1463042596-61703-4-git-send-email-hekuang@huawei.com> <20160512130925.GG20258@kernel.org> <5734E649.80505@gmail.com> <57358003.3020203@huawei.com> <6108abe8-4508-c440-969f-5f9d8ee83131@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6108abe8-4508-c440-969f-5f9d8ee83131@gmail.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, May 13, 2016 at 08:27:29AM -0600, David Ahern escreveu: > On 5/13/16 1:19 AM, Hekuang wrote: > > > What about putting the build id cache under the symfs? so instead of > > > dropping the symfs check and it to the path for the build id cache. > > I think your intention is to reference symbol files in one place > > instead of two. So there're two possible approaches, one is all > > in buildid-cache, but in practice, I found lots of binaries in > > symfs even not contains valid buildid, so this way is not work. > > The other one is all in symfs. It seems ok, but one problem I > > should point out, with my test environment as an example, the > > symfsdir is $(TARGET_ROOTFS),and by default buildid_dir is > > $(TARGET_ROOTFS)/$(HOME)/.debug/, host perf does not know > > $(HOME) folder in target and we should copy the debug folder > > to $(TARGET_ROOTFS), which is readonly in the target. For me, it's > > easier to use 'buildid-cache -a vdso-xxxx' to add that into host > > buildid-cache than copy debug folder from $(HOME) to readonly > > $(TARGET_ROOTFS). > > Without the stale concern, I prefer the two places(buildid-dir in > > host and target symfs) way. > > The intention of symfs is every single file opened by perf is relative to > that directory. As I recall when I added that option in early 2011 I made > sure that statement is true. I think it is best to maintain that design. Ok, so we can introduce --dso-prefix for Hekuang's use case, i.e. be able to lookup by build-id, fallbacking to a (possibly read-only) directory. This way the existing --symfs semantic remains written in stone. - Arnaldo