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=-5.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=unavailable 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 4635FC74A21 for ; Wed, 10 Jul 2019 15:39:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E75C2087F for ; Wed, 10 Jul 2019 15:39:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="lsDAwrPm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728005AbfGJPi7 (ORCPT ); Wed, 10 Jul 2019 11:38:59 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:36702 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726105AbfGJPi7 (ORCPT ); Wed, 10 Jul 2019 11:38:59 -0400 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 x6AFXpjV140644; Wed, 10 Jul 2019 15:37:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=message-id : mime-version : date : from : to : cc : subject : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=RoOPOjQgj2XYASbiBhpR/1oApLKROklq3dcoMH9Dp4M=; b=lsDAwrPmHqsQB+Iaaw5ADhMtvebDrQoFVAS1sBi13MaorrlgkynlYaVcm2iwBodPz3s4 q2kMQ+Bg6wSRPVnmPEoQL6mbarYBOSptxvQ4ONVAAcHnlhEpCJwbGXWklNeRgByFHDyX nN5zW2KhsyRjrWnuqITsJ/3Q9l7MQ173HVfZCli9T8wTj4hL8QNw+xl3h8a595OyYJ57 K8CEwpP8wjYlxD0Zs9PtZNSMBR23m10B8NQLMlvKvx5bRC8oimxJC2V+YRGIKS9tu2fC G5CrVL6oYOWOzdB/OlsgtMC/pAhp+g4z3CMpfvILq4tWtMtMuLxnk+MKisQBAhifkPLc ag== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2tjm9qtwwf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jul 2019 15:37:58 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6AFWjX3056498; Wed, 10 Jul 2019 15:37:57 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3030.oracle.com with ESMTP id 2tmwgxjj8e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 10 Jul 2019 15:37:57 +0000 Received: from aserp3030.oracle.com (aserp3030.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x6AFbvkv069541; Wed, 10 Jul 2019 15:37:57 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2tmwgxjj88-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jul 2019 15:37:57 +0000 Received: from abhmp0022.oracle.com (abhmp0022.oracle.com [141.146.116.28]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x6AFboMR015946; Wed, 10 Jul 2019 15:37:50 GMT Message-Id: <201907101537.x6AFboMR015946@aserv0122.oracle.com> Received: from localhost (/10.159.211.102) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 10 Jul 2019 08:37:49 -0700 MIME-Version: 1.0 Date: Wed, 10 Jul 2019 08:37:50 -0700 (PDT) From: Kris Van Hees To: netdev@vger.kernel.org, bpf@vger.kernel.org, dtrace-devel@oss.oracle.com, linux-kernel@vger.kernel.org Cc: rostedt@goodmis.org, mhiramat@kernel.org, acme@kernel.org, ast@kernel.org, daniel@iogearbox.net, Peter Zijlstra , Chris Mason Subject: [PATCH V2 0/1] tools/dtrace: initial implementation of DTrace Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9314 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907100176 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is version 2 of the patch, incorporating feedback from Peter Zijlstra and Arnaldo Carvalho de Melo. Changes in Makefile: - Remove -I$(srctree)/tools/perf from KBUILD_HOSTCFLAGS since it is not actually used. Changes in dt_bpf.c: - Remove unnecessary PERF_EVENT_IOC_ENABLE. Changes in dt_buffer.c: - Use ring_buffer_read_head() and ring_buffer_write_tail() to avoid use of volatile. - Handle perf events that wrap around the ring buffer boundary. - Remove unnecessary PERF_EVENT_IOC_ENABLE. Changes in bpf_sample.c: - Use PT_REGS_PARM1(x), etc instead of my own macros. Adding PT_REGS_PARM6(x) in bpf_sample.c because we need to be able to support up to 6 arguments passed by registers. This patch is also available, applied to bpf-next, at the following URL: https://github.com/oracle/dtrace-linux-kernel/tree/dtrace-bpf As suggested in feedback to my earlier patch submissions, this code takes an approach to avoid kernel code changes as much as possible. The current patch does not involve any kernel code changes. Further development of this code will continue with this approach, incrementally adding features to this first minimal implementation. The goal is a fully featured and functional DTrace implementation involving kernel changes only when strictly necessary. The code presented here supports two very basic functions: 1. Listing probes that are used in BPF programs # dtrace -l -s bpf_sample.o ID PROVIDER MODULE FUNCTION NAME 18876 fbt vmlinux ksys_write entry 70423 syscall vmlinux write entry 2. Loading BPF tracing programs and collecting data that they generate # dtrace -s bpf_sample.o CPU ID 15 70423 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c 15 18876 0xffff8c0968bf8ec0 0x00000000000001 0x0055e019eb3f60 0x0000000000002c ... Only kprobes and syscall tracepoints are supported since this is an initial patch. It does show the use of a generic BPF function to implement the actual probe action, called from two distinct probe types. Follow-up patches will add more probe types, add more tracing features from the D language, add support for D script compilation to BPF, etc. The implementation makes use of libbpf for handling BPF ELF objects, and uses the perf event output ring buffer (supported through BPF) to retrieve the tracing data. The next step in development will be adding support to libbpf for programs using shared functions from a collection of functions included in the BPF ELF object (as suggested by Alexei). The code is structured as follows: tools/dtrace/dtrace.c = command line utility tools/dtrace/dt_bpf.c = interface to libbpf tools/dtrace/dt_buffer.c = perf event output buffer handling tools/dtrace/dt_fbt.c = kprobes probe provider tools/dtrace/dt_syscall.c = syscall tracepoint probe provider tools/dtrace/dt_probe.c = generic probe and probe provider handling code This implements a generic interface to the actual probe providers (dt_fbt and dt_syscall). tools/dtrace/dt_hash.c = general probe hashing implementation tools/dtrace/dt_utils.c = support code (manage list of online CPUs) tools/dtrace/dtrace.h = API header file (used by BPF program source code) tools/dtrace/dtrace_impl.h = implementation header file tools/dtrace/bpf_sample.c = sample BPF program using two probe types I included an entry for the MAINTAINERS file. I offer to actively maintain this code, and to keep advancing its development. Cheers, Kris Van Hees