From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH 3/3] ftrace: trace single pid for function graph tracer Date: Wed, 03 Dec 2008 15:36:29 -0800 Message-ID: References: <20081203203656.776893226@goodmis.org> <20081203203829.362295724@goodmis.org> <20081203124915.2eb9e7cd.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: (Steven Rostedt's message of "Wed, 3 Dec 2008 15:52:24 -0500 (EST)") Sender: linux-kernel-owner@vger.kernel.org To: Steven Rostedt Cc: Andrew Morton , linux-kernel@vger.kernel.org, mingo@elte.hu, fweisbec@gmail.com, peterz@infradead.org, arjan@infradead.org, dave@linux.vnet.ibm.com, containers@lists.osdl.org, sukadev@linux.vnet.ibm.com, serue@us.ibm.com, srostedt@redhat.com List-Id: containers.vger.kernel.org Steven Rostedt writes: >> > # echo $$ > /debugfs/tracing/set_ftrace_pid >> > # echo function_graph > /debugfs/tracing/current_tracer >> > >> > Will cause only the current task to be traced. Note, the trace flags are >> > also inherited by child processes, so the children of the shell >> > will also be traced. >> >> Where did we end up on the pids-arent-unique issue? Gave up? > > Nah, patch 2 opens the door for a solution. I'm just pawning the work off > to the container folks ;-) The way patch 2 uses pids is just stupid. It has nothing to do with pids aren't unique. You do a full walk of the process list instead of using the hash table. It makes me think that task->pid really should go away because with it there people don't bother to look and see how things normally work. Eric