From: Greg KH <gregkh@linuxfoundation.org>
To: KY Srinivasan <kys@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"olaf@aepfle.de" <olaf@aepfle.de>,
Stephen Hemminger <sthemmin@microsoft.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"apw@canonical.com" <apw@canonical.com>,
"marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
"devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
"leann.ogasawara@canonical.com" <leann.ogasawara@canonical.com>
Subject: Re: [PATCH 10/17] hyper-v: trace vmbus_open()
Date: Sat, 4 Nov 2017 12:05:20 +0100 [thread overview]
Message-ID: <20171104110520.GA425@kroah.com> (raw)
In-Reply-To: <DM5PR21MB047600F4228DF4BA8A2DB583A05F0@DM5PR21MB0476.namprd21.prod.outlook.com>
On Wed, Nov 01, 2017 at 05:43:08PM +0000, KY Srinivasan wrote:
>
>
> > -----Original Message-----
> > From: devel [mailto:driverdev-devel-bounces@linuxdriverproject.org] On
> > Behalf Of Steven Rostedt
> > Sent: Tuesday, October 31, 2017 6:10 AM
> > To: Greg KH <gregkh@linuxfoundation.org>
> > Cc: olaf@aepfle.de; Stephen Hemminger <sthemmin@microsoft.com>;
> > jasowang@redhat.com; linux-kernel@vger.kernel.org; apw@canonical.com;
> > marcelo.cerri@canonical.com; devel@linuxdriverproject.org; Vitaly
> > Kuznetsov <vkuznets@redhat.com>; leann.ogasawara@canonical.com
> > Subject: Re: [PATCH 10/17] hyper-v: trace vmbus_open()
> >
> > On Tue, 31 Oct 2017 13:48:00 +0100
> > Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > > > I don't see how that information can be extracted easily without a
> > > > tracepoint here. Am I missing something?
> > >
> > > Wasn't one of the outcomes of the conference last week the fact that for
> > > ftrace + ebpf we could get access to the structures of the function
> > > parameters? Or that work would soon be showing up?
> >
> > I told Linus that I'll start building an infrastructure on function
> > tracing to see what we can do. But it may be very limited in features.
> > I don't believe eBPF can follow arbitrary data structure pointers
> > without helper functions. Which doesn't exist for this type of code yet.
> >
> > >
> > > It just feels "wrong" to add a tracepoint for a function call, like it
> > > is a duplication of work/functionality we already have.
> >
> > We don't already have it. We may have something in a year (or two) that
> > may be able to get all the data that is requested here. But it's going
> > to take lots of RFC patch sets and brain storming to come up with
> > something that everyone is satisfied with.
> >
> > In other words, the functionality is currently in vaporware state.
>
> Greg,
>
> The added memory overhead is very minimal, and the added tracing support is extremely useful for
> our debugging. If you don't mind, I would like to have this tracing support.
Ok, it's your subsystem, you get to handle the long-term maintenance of
these :)
Now merged,
greg k-h
next prev parent reply other threads:[~2017-11-04 11:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-29 19:20 [PATCH 00/17] Drivers: hv: vmbus: Add tracing to VMBus kys
2017-10-29 19:21 ` [PATCH 01/17] hyper-v: trace vmbus_on_msg_dpc() kys
2017-10-29 19:21 ` [PATCH 02/17] hyper-v: trace vmbus_on_message() kys
2017-10-29 19:21 ` [PATCH 03/17] hyper-v: trace vmbus_onoffer() kys
2017-10-29 19:21 ` [PATCH 04/17] hyper-v: trace vmbus_onoffer_rescind() kys
2017-10-29 19:21 ` [PATCH 05/17] hyper-v: trace vmbus_onopen_result() kys
2017-10-29 19:21 ` [PATCH 06/17] hyper-v: trace vmbus_ongpadl_created() kys
2017-10-29 19:21 ` [PATCH 07/17] hyper-v: trace vmbus_ongpadl_torndown() kys
2017-10-29 19:21 ` [PATCH 08/17] hyper-v: trace vmbus_onversion_response() kys
2017-10-29 19:21 ` [PATCH 09/17] hyper-v: trace vmbus_request_offers() kys
2017-10-29 19:21 ` [PATCH 10/17] hyper-v: trace vmbus_open() kys
2017-10-29 20:59 ` Greg KH
2017-10-30 8:16 ` Vitaly Kuznetsov
2017-10-30 8:45 ` Greg KH
2017-10-30 10:07 ` Vitaly Kuznetsov
2017-10-30 10:32 ` Greg KH
2017-10-30 14:31 ` Steven Rostedt
2017-10-31 12:48 ` Greg KH
2017-10-31 13:10 ` Steven Rostedt
2017-11-01 17:43 ` KY Srinivasan
2017-11-04 11:05 ` Greg KH [this message]
2017-11-04 15:09 ` KY Srinivasan
2017-10-31 17:41 ` Stephen Hemminger
2017-10-29 19:21 ` [PATCH 11/17] hyper-v: trace vmbus_close_internal() kys
2017-10-29 19:21 ` [PATCH 12/17] hyper-v: trace vmbus_establish_gpadl() kys
2017-10-29 19:21 ` [PATCH 13/17] hyper-v: trace vmbus_teardown_gpadl() kys
2017-10-29 19:21 ` [PATCH 14/17] hyper-v: trace vmbus_negotiate_version() kys
2017-10-29 19:21 ` [PATCH 15/17] hyper-v: trace vmbus_release_relid() kys
2017-10-29 19:21 ` [PATCH 16/17] hyper-v: trace vmbus_send_tl_connect_request() kys
2017-10-29 19:21 ` [PATCH 17/17] hyper-v: trace channel events kys
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