From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753487AbbFDVtA (ORCPT ); Thu, 4 Jun 2015 17:49:00 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:42707 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752074AbbFDVs7 (ORCPT ); Thu, 4 Jun 2015 17:48:59 -0400 Message-ID: <5570C7C2.9030900@hitachi.com> Date: Fri, 05 Jun 2015 06:48:50 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Alexei Starovoitov , Ingo Molnar , pi3orama CC: "Wangnan (F)" , Arnaldo Carvalho de Melo , "linux-kernel@vger.kernel.org" , Adrian Hunter , Brendan Gregg , Daniel Borkmann , David Ahern , He Kuang , Jiri Olsa , Kaixu Xia , Madhavan Srinivasan , Michael Ellerman , Namhyung Kim , Peter Zijlstra , Sukadev Bhattiprolu , Zefan Li , Arnaldo Carvalho de Melo , Alexei Starovoitov , cti.systems-productivity-manager.ts@hitachi.com Subject: Re: [GIT PULL 0/6] perf/core improvements and fixes References: <1433371238-14572-1-git-send-email-acme@kernel.org> <20150604054854.GA10969@gmail.com> <556FEB32.8040909@huawei.com> <20150604072153.GA18983@gmail.com> <557021D3.7070900@huawei.com> <20150604124033.GA10580@gmail.com> <0108CD89-BFFA-4A68-90AE-A34597777641@163.com> <20150604140412.GB14445@gmail.com> <55707B3F.2070704@plumgrid.com> In-Reply-To: <55707B3F.2070704@plumgrid.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/06/05 1:22, Alexei Starovoitov wrote: > On 6/4/15 7:04 AM, Ingo Molnar wrote: >>>> # perf record -e bpf_source.c cmdline >>>> >>>> to create a eBPF filter from source, >>>> >>>> Use >>>> >>>> # perf record -e bpf_object.o cmdline >>>> >>>> to create a eBPF filter from object intermedia. >>>> >>>> Use >>>> >>>> # perf bpf compile bpf_source.c --kbuild=kernel-build-dir -o bpf_object.o >>>> >>>> to create the .o >>>> >>>> I think this should be enough. Currently only the second case has been implemented. >> So if users cannot actually generate .o files then it's premature to merge this in >> such an incomplete form! >> >> It should be possible to use a feature that we are merging. > > of course it's usable :) There is some confusion here. > To compile .c into .o one can easily use > clang -O2 -emit-llvm -c file.c -o - | llc -march=bpf -o file.o > any version of clang is ok, > llc needs to be fresh with bpf backend. > > For a lot of cases kernel headers are not needed, so above > will work fine. > For our TC examples we recommend to use 'bcc' alias: > bcc() { > clang -O2 -emit-llvm -c $1 -o - | llc -march=bpf -filetype=obj -o > "`basename $1 .c`.o" > } > then compiling as easy as 'bcc file.c' > > What Wang mentioned that we're working on is fully integrated 'bcc'. > It will use clang/llvm as libraries, so no intermediate steps will > be needed, but some folks will always have concerns about > ultra-embedded environments where even 20Mb of libllvm.so is too much. > > So I think we need to support both 'perf record -e file.[co]' I think we'd better make 'perf record -e file.c' default and '-e file.o' should be an option. Thank you, > > -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com