From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [patch 37/37] LTTng instrumentation net Date: Thu, 24 Apr 2008 12:13:37 -0400 Message-ID: <20080424161337.GA22874@Krystal> References: <20080424150324.802695381@polymtl.ca> <20080424151408.991424268@polymtl.ca> <4810ACB4.501@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: akpm@linux-foundation.org, Ingo Molnar , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Pavel Emelyanov Return-path: Content-Disposition: inline In-Reply-To: <4810ACB4.501@openvz.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org * Pavel Emelyanov (xemul@openvz.org) wrote: > Mathieu Desnoyers wrote: > > Network core events. > > > > Added markers : > > > > net_del_ifa_ipv4 > > net_dev_receive > > net_dev_xmit > > net_insert_ifa_ipv4 > > net_socket_call > > net_socket_create > > net_socket_recvmsg > > net_socket_sendmsg > > Network "core" events are not limited with the above calls. > True. This is by no mean an exhaustive list of network events. It just happens to be the ones which has been useful to LTT/LTTng users for the past ~10 years. > Besides, real "core" events already sent notifications about themselves. > Why do we need additional hooks? > I doubt the current notification hooks have a performance impact as small as the proposed markers. Which notification mechanism do you refer to ? It could be interesting to put markers in there instead. The goal behind this is to feed information to a general purpose tracer like lttng, a scripting mechanism like systemtap or a special-purpose tracer like ftrace. I think that the most important instrumentation in this patchset is the xmit/recv of a packet at the device level. The net_socket_* instrumentation could eventually be replaced by an architecture specfic system call parameters instrumentation. Mathieu > > Signed-off-by: Mathieu Desnoyers > > CC: netdev@vger.kernel.org > > --- > > net/core/dev.c | 6 ++++++ > > net/ipv4/devinet.c | 6 ++++++ > > net/socket.c | 19 +++++++++++++++++++ > > 3 files changed, 31 insertions(+) > -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68