From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46387) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSq1O-0000Qa-Qq for qemu-devel@nongnu.org; Wed, 26 Mar 2014 11:45:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSq1I-0002mt-08 for qemu-devel@nongnu.org; Wed, 26 Mar 2014 11:45:42 -0400 Received: from smtp.polymtl.ca ([132.207.4.11]:54097) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSq1H-0002lk-Oq for qemu-devel@nongnu.org; Wed, 26 Mar 2014 11:45:35 -0400 Message-ID: <5332F60F.9020105@polymtl.ca> Date: Wed, 26 Mar 2014 11:45:19 -0400 From: Mohamad Gebai MIME-Version: 1.0 References: <1395680694-27758-1-git-send-email-alex.bennee@linaro.org> <20140325095627.GO17172@stefanha-thinkpad.redhat.com> <8761n2nxix.fsf@linaro.org> <20140326082707.GE25917@stefanha-thinkpad.muc.redhat.com> In-Reply-To: <20140326082707.GE25917@stefanha-thinkpad.muc.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] trace: teach lttng backend to use format strings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , =?ISO-8859-1?Q?Alex_Benn=E9e?= Cc: mohamad.gebai@gmail.com, qemu-devel@nongnu.org, vilanova@ac.upc.edu I can confirm that it works for me, I can see the disk image file name=20 in the payload of brdv_open_common events. Mohamad On 03/26/2014 04:27 AM, Stefan Hajnoczi wrote: > On Tue, Mar 25, 2014 at 02:49:42PM +0000, Alex Benn=E9e wrote: >> Stefan Hajnoczi writes: >> >>> On Mon, Mar 24, 2014 at 05:04:54PM +0000, alex.bennee@linaro.org wrot= e: >>>> From: Alex Benn=E9e >>>> >>>> This makes the UST backend pay attention to the format string argume= nts >>>> that are defined when defining payload data. With this you can now >>>> ensure integers are reported in hex mode if you want. >>>> >>>> Signed-off-by: Alex Benn=E9e >>>> --- >>>> scripts/tracetool/__init__.py | 13 +++++++++++-- >>>> scripts/tracetool/backend/ust.py | 16 ++++++++++++---- >>>> 2 files changed, 23 insertions(+), 6 deletions(-) >>> How are strings handled, can LTTng copy them from the QEMU process' >>> memory space? >> lttng provides ctf_string for passing strings to the payload. But I >> wouldn't expect to use them for the result of format string calculatio= ns >> as that would defeat the point of the low impact tracing. >> >> There are a number of trace-events that pass strings for various thing= s. >> I've not actually experimented with the output of any of them though. > Sounds like it should work but can you test it? Try enabling the > bdrv_open_common() trace event when booting a guest. You should see th= e > filename of the disk image file. > > Stefan