From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753047AbbGNDIW (ORCPT ); Mon, 13 Jul 2015 23:08:22 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:35029 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752665AbbGNDIV (ORCPT ); Mon, 13 Jul 2015 23:08:21 -0400 Message-ID: <55A47D24.5010703@plumgrid.com> Date: Mon, 13 Jul 2015 20:08:20 -0700 From: Alexei Starovoitov User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: He Kuang , rostedt@goodmis.org, masami.hiramatsu.pt@hitachi.com, acme@kernel.org, a.p.zijlstra@chello.nl, mingo@redhat.com, namhyung@kernel.org, jolsa@kernel.org CC: wangnan0@huawei.com, pi3orama@163.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v5 3/3] bpf: Introduce function for outputing trace event data References: <1436839171-31527-1-git-send-email-hekuang@huawei.com> <1436839171-31527-4-git-send-email-hekuang@huawei.com> In-Reply-To: <1436839171-31527-4-git-send-email-hekuang@huawei.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/13/15 6:59 PM, He Kuang wrote: > There're scenarios that we need an eBPF program to record not only > kprobe point args, but also the PMU counters, time latencies or the > number of cache misses between two probe points and other information > when the probe point is entered. > > This patch adds a new trace event to establish infrastruction for bpf to > output data to perf. Userspace perf tools can detect and use this event > as using the existing tracepoint events. > > New bpf trace event entry in debugfs: > > /sys/kernel/debug/tracing/events/bpf/bpf_output_data > > Userspace perf tools detect the new tracepoint event as: > > bpf:bpf_output_data [Tracepoint event] > > Data in ring-buffer of perf events added to this event will be polled > out, sample types and other attributes can be adjusted to those events > directly without touching the original kprobe events. > > The bpf helper function gives eBPF program ability to output data as > perf sample event. This helper simple call the new trace event and > userspace perf tools can record the BPF ftrace event to collect those > records. > > Signed-off-by: He Kuang Looks good to me. Acked-by: Alexei Starovoitov