From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F41FEC43381 for ; Sat, 23 Feb 2019 04:24:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B89D32084F for ; Sat, 23 Feb 2019 04:24:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="2VePbyId" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725859AbfBWEY0 (ORCPT ); Fri, 22 Feb 2019 23:24:26 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:56378 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725821AbfBWEY0 (ORCPT ); Fri, 22 Feb 2019 23:24:26 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x1N4J1aX072353; Sat, 23 Feb 2019 04:24:23 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : subject : message-id : mime-version : content-type; s=corp-2018-07-02; bh=vtODrFGYTG5WleGG1y4TSNo/Fd2O8gtzcokaVN2QwRU=; b=2VePbyIdOhEJ2DwHWSPcLRNjBKw2Q3gVNNcQee+wzBANdXYBm3oXX1lL1PIs//TQP2z9 /4BRBQ1QM7TsEXRobeBiye0cqNSjPRBuVGIIikf2SwbxaV2Mr9YUb91njnVAtEPjkUF6 wv7+Ke9/Ty/eE2b6uIKIyYy1Sx996z394lderZ4+/GGvmgQlsrI3EHRW/OxzNKDQav6K BCu3QKVw0R2BzlkGqQQc7p/vhePkYNsvn/ZozskHim78N3f7wZFMWT+ciG3BrnULZJVM c/XeuQiYxsWPxmoBBfGDF1qXwL8YwnpdXFgxryiNDxMql+dE45X0d2SKZ0xlNmVIwuZh uw== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2120.oracle.com with ESMTP id 2qtxtr80k3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 23 Feb 2019 04:24:23 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x1N4OMR5029345 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 23 Feb 2019 04:24:23 GMT Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x1N4OMma015719; Sat, 23 Feb 2019 04:24:22 GMT Received: from localhost (/10.159.211.98) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 22 Feb 2019 20:24:22 -0800 Date: Fri, 22 Feb 2019 23:24:12 -0500 From: Kris Van Hees To: lsf-pc@lists.linux-foundation.org, bpf@vger.kernel.org Subject: [LSF/MM TOPIC] BPF: Extending eBPF as a generic tracing engine Message-ID: <20190223042412.GV25582@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9175 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=858 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902230028 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Topic: Extending eBPF as a generic tracing engine My presentation covers a few new features to the eBPF implementation in support of tracing tools. The main goal is to allow tracing tools the ability to encode actions with probes/events, beyond the context of what the current probes/events provide. The features to discuss are: - Allowing BPF-to-BPF tail-calling between BPF programs of different program types (ussing a context conversion/casting mechanism that BPF program types can provide. This patch is being posted to the netdev group this weekend, along with an example on how to use it. - Using the context conversion mechanism to associate task info with probe/event context, and have a BPF program operate on that, which reduces the dependency (or need) for helper functions. - Consider the option of having BPF program sub-types (for some program types), which could even provide for loadable modules to implement some specific extensions to a more generic BPF program type. - Extending the context handling code and access checking to allow for pointer references to auxilliary structs (to an arbitrary depth). This makes it possible to do a lot more with contexts, such as having it store a pointer to a trace output buffer so you can have BPF instructions store to it directly. The talk will focus on why this will help tracing a lot, and how it will advance BPF as a tracing facility. I want to solicit feedback on these features so there can be common road forward to enhancing tracing based on BPF.