From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754222AbeCVBbm (ORCPT ); Wed, 21 Mar 2018 21:31:42 -0400 Received: from mga06.intel.com ([134.134.136.31]:22282 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752293AbeCVBbl (ORCPT ); Wed, 21 Mar 2018 21:31:41 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,342,1517904000"; d="scan'208";a="213749036" Subject: Re: [PATCH] perf util: Display warning when perf report/annotate is missing some libs To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com References: <1515668586-14327-1-git-send-email-yao.jin@linux.intel.com> <20180111153028.GB20406@krava> <42a90e87-f2fd-293d-bd25-591fcdff14e1@linux.intel.com> <20180321153807.GA2707@krava> <20180321154035.GC24312@kernel.org> <20180321154315.GD24312@kernel.org> <20180321160446.GB2707@krava> <20180321185237.GF24312@kernel.org> From: "Jin, Yao" Message-ID: <1fac9573-00bb-1c7f-c773-3b69410c77ed@linux.intel.com> Date: Thu, 22 Mar 2018 09:31:37 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180321185237.GF24312@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/22/2018 2:52 AM, Arnaldo Carvalho de Melo wrote: > Em Wed, Mar 21, 2018 at 05:04:46PM +0100, Jiri Olsa escreveu: >> On Wed, Mar 21, 2018 at 12:43:15PM -0300, Arnaldo Carvalho de Melo wrote: >>> Em Wed, Mar 21, 2018 at 12:40:35PM -0300, Arnaldo Carvalho de Melo escreveu: >>>> Em Wed, Mar 21, 2018 at 04:38:07PM +0100, Jiri Olsa escreveu: >>>>> On Wed, Mar 21, 2018 at 10:11:10AM +0800, Jin, Yao wrote: >>>>>> Hi Jiri, >>>>>> >>>>>> I'm still thinking it's worth displaying the warning when perf missing some >>>>>> libraries. >>>>>> >>>>>> Somebody just told me that perf didn't work well. While after some >>>>>> investigations, I found it's just missing some libraries when building the >>>>>> perf. >>>>>> >>>>>> But I have spent some time on getting the root cause. If with this patch, it >>>>>> should be very easily to know that. > >>>>> true.. Arnaldo, any feedback on this one? > >>>> Lemme re-read the thread... > >>> Well, how about we make it harder to build without key libraries? I.e. >>> if we detect that what we consider a core set of libraries isn't found >>> in the system, then we stop the build, warn about it and ask the user to >>> confirm that the build should proceed by passing some explicit >>> -DI_KNOW_WHAT_I_AM_DOING___PROCEED=doit > >> hum, not sure we want to complicate the build even more than it >> is now :-\ and IMO it still won't help much in Jin's problem, >> if user forces the build anyway > > Well, if a user _forces_ a build, not taking into consideration a > warning that _is_ emitted and _stops_ the build, about the functionality > it will lose by doing forcing the build, then comes back and complains > that that functionality is not present, then it becomes difficult to > help this user... :-) > > On the other hand, if the user forgets to install an important library, > the warning is emitted but the build proceeds, no explicit action was > performed, just a warning wasn't noticed, and the user complains, then > I'd say: "hey, are you sure library foo devel files were present when > you build it?", i.e. the support back and forth Jin is trying to avoid. > > And for users that _saw_ the warning, _knew_ they _didn't_ want that > functionality, to be reminded while running, say 'perf report' that > something they _decided not to have_ isn't present, then that could be > annoying, no? > > Lemme try another idea: what if we do something like gcc does and print > the features present when showing the version? > > I.e.: > > [acme@jouet perf]$ gcc -v > Using built-in specs. > COLLECT_GCC=/usr/bin/gcc > COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/7/lto-wrapper > OFFLOAD_TARGET_NAMES=nvptx-none > OFFLOAD_TARGET_DEFAULT=1 > Target: x86_64-redhat-linux > Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-libmpx --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux > Thread model: posix > gcc version 7.3.1 20180303 (Red Hat 7.3.1-5) (GCC) > [acme@jouet perf]$ > > - Arnaldo > Is this too complicated for perf newbie to understand? For my problem, the mistake only occurs on perf newbie. I just think, it'd better return a direct and clear message to them. Maybe they don't know or don't use -v or -vv to do more investigation by themselves. Thanks Jin Yao