Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755857AbYFVSDo (ORCPT ); Sun, 22 Jun 2008 14:03:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752847AbYFVSDh (ORCPT ); Sun, 22 Jun 2008 14:03:37 -0400 Received: from ug-out-1314.google.com ([66.249.92.171]:45401 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752807AbYFVSDg (ORCPT ); Sun, 22 Jun 2008 14:03:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=sXKRrBADJtwq1jNWeW3qxsFfJRP01eiDMp2PrbYI/++2doDLbGsLduHv4tgWGGiU9l dPjJk/EtXL61pYRvMjyNeHrEOBDWCn5aoc2EQe4pJR2iJVQObkiAINwb4n7Ml1ZI4NnM zq8kxjb3oMASzYaw2SWYnnKTlRMWhFiGbAD78= Date: Sun, 22 Jun 2008 21:59:28 +0400 From: Alexey Dobriyan To: Mathieu Desnoyers Cc: Peter Zijlstra , Masami Hiramatsu , Steven Rostedt , "Frank Ch. Eigler" , Ingo Molnar , LKML , systemtap-ml , Hideo AOKI Subject: Re: [RFC] Tracepoint proposal Message-ID: <20080622175928.GA5022@martell.zuzino.mipt.ru> References: <485BE2C6.1080901@redhat.com> <20080620174529.GB10943@Krystal> <1213992446.3223.195.camel@lappy.programming.kicks-ass.net> <20080622171135.GA19432@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080622171135.GA19432@Krystal> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2388 Lines: 61 On Sun, Jun 22, 2008 at 01:11:35PM -0400, Mathieu Desnoyers wrote: > Tracepoint proposal > > - Tracepoint infrastructure > - In-kernel users > - Complete typing, verified by the compiler > - Dynamically linked and activated > > - Marker infrastructure > - Exported API to userland > - Basic types only > > - Dynamic vs static > - In-kernel probes are dynamically linked, dynamically activated, connected to > tracepoints. Type verification is done at compile-time. Those in-kernel > probes can be a probe extracting the information to put in a marker or a > specific in-kernel tracer such as ftrace. > - Information sinks (LTTng, SystemTAP) are dynamically connected to the > markers inserted in the probes and are dynamically activated. > > - Near instrumentation site vs in a separate tracer module > > A probe module, only if provided with the kernel tree, could connect to internal > tracing sites. This argues for keeping the tracepoing probes near the > instrumentation site code. However, if a tracer is general purpose and exports > typing information to userspace through some mechanism, it should only export > the "basic type" information and could be therefore shipped outside of the > kernel tree. > > In-kernel probes should be integrated to the kernel tree. They would be close to > the instrumented kernel code and would translate between the in-kernel > instrumentation and the "basic type" exports. Other in-kernel probes could > provide a different output (statistics available through debugfs for instance). > ftrace falls into this category. > > Generic or specialized information "sinks" (LTTng, systemtap) could be connected > to the markers put in tracepoint probes to extract the information to userspace. > They would extract both typing information and the per-tracepoint execution > information to userspace. > > Therefore, the code would look like : > > kernel/sched.c: > > #include "sched-trace.h" > > schedule() > { > ... > trace_sched_switch(prev, next); > ... > } Once this is accepted you're going to add hundreds of such calls to every core subsystem, right? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/