From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Subject: Re: [PATCH -tip -v11 11/11] tracing: Add kprobes event profiling 	interface
Date: Fri, 10 Jul 2009 10:47:27 +0530
Message-ID: <20090710051727.GA1745@in.ibm.com>
References: <20090709202220.13223.97114.stgit@localhost.localdomain> <20090709202327.13223.16418.stgit@localhost.localdomain>
Reply-To: ananth@in.ibm.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,         lkml<linux-kernel@vger.kernel.org>,         systemtap<systemtap@sources.redhat.com>, kvm<kvm@vger.kernel.org>,         DLE<dle-develop@lists.sourceforge.net>,         Christoph Hellwig <hch@infradead.org>,         Frederic Weisbecker <fweisbec@gmail.com>,         Tom Zanussi <tzanussi@gmail.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Return-path: <systemtap-return-12927-gls-systemtap=m.gmane.org@sourceware.org>
Content-Disposition: inline
In-Reply-To: <20090709202327.13223.16418.stgit@localhost.localdomain>
List-Unsubscribe: <mailto:systemtap-unsubscribe-gls-systemtap=m.gmane.org@sourceware.org>
List-Subscribe: <mailto:systemtap-subscribe@sourceware.org>
List-Post: <mailto:systemtap@sourceware.org>
List-Help: <mailto:systemtap-help@sourceware.org>, <http://sourceware.org/lists.html#faqs>
Sender: systemtap-owner@sourceware.org
List-Id: kvm.vger.kernel.org

On Thu, Jul 09, 2009 at 04:23:27PM -0400, Masami Hiramatsu wrote:
> Add profiling interaces for each kprobes event.

...

>  /* Kprobe handler */
>  static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
>  {
> @@ -772,6 +809,8 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
>  	unsigned long irq_flags;
>  	struct ftrace_event_call *call = &tp->call;
> 
> +	tp->nhits++;
> +

If you just are looking for a count and aren't bothered about its
accuracy, this is fine. Else, handlers can run in parallel ;-)

Ananth