From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=49195 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OGDRk-00056r-4l for qemu-devel@nongnu.org; Sun, 23 May 2010 11:50:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OGDRg-0001BW-Hp for qemu-devel@nongnu.org; Sun, 23 May 2010 11:50:36 -0400 Received: from fmmailgate03.web.de ([217.72.192.234]:35807) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OGDRg-0001BL-75 for qemu-devel@nongnu.org; Sun, 23 May 2010 11:50:32 -0400 Message-ID: <4BF94EC6.3070700@web.de> Date: Sun, 23 May 2010 17:50:30 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1274562503-10713-1-git-send-email-stefanha@linux.vnet.ibm.com> <1274562503-10713-4-git-send-email-stefanha@linux.vnet.ibm.com> In-Reply-To: <1274562503-10713-4-git-send-email-stefanha@linux.vnet.ibm.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8DE563DEE852D028EB1081D8" Sender: jan.kiszka@web.de Subject: [Qemu-devel] Re: [PATCH 3/5] trace: Add LTTng Userspace Tracer backend List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Anthony Liguori , qemu-devel@nongnu.org, kvm@vger.kernel.org, Prerna Saxena This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8DE563DEE852D028EB1081D8 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Stefan Hajnoczi wrote: > This patch adds LTTng Userspace Tracer (UST) backend support. The UST > system requires no kernel support but libust and liburcu must be > installed. >=20 > $ ./configure --trace-backend ust > $ make >=20 > Start the UST daemon: > $ ustd & >=20 > List available tracepoints and enable some: > $ ustctl --list-markers $(pgrep qemu) > [...] > {PID: 5458, channel/marker: ust/paio_submit, state: 0, fmt: "acb %p > opaque %p sector_num %lu nb_sectors %lu type %lu" 0x4b32ba} > $ ustctl --enable-marker "ust/paio_submit" $(pgrep qemu) >=20 > Run the trace: > $ ustctl --create-trace $(pgrep qemu) > $ ustctl --start-trace $(pgrep qemu) > [...] > $ ustctl --stop-trace $(pgrep qemu) > $ ustctl --destroy-trace $(pgrep qemu) >=20 > Trace results can be viewed using lttv-gui. >=20 > More information about UST: > http://lttng.org/ust >=20 > Signed-off-by: Stefan Hajnoczi > --- > I wrote this as part of trying out UST. Although UST is promising, the= > usability is poor at the moment. I was hoping it would be better, but I'm not really surprised. >=20 > The dependencies include the lttv trace viewer which I had to build fro= m source > (and it required a makefile tweak to build). Luckily libust, liburcu, = and > ust-bin are packaged on my distro. >=20 > Error messages are periodically printed by the UST code when running QE= MU. I > haven't investigated but this is may be due to signals interrupting UST= 's > thread in poll(). >=20 > Finally, the UST header files include some userspace ported kernel > infrastructure and pollute the namespace. I had to add some #undefs to= get > QEMU to build after including UST headers. >=20 > I don't see LTTng UST as a default option at the moment. Hopefully thi= s will > change in the future. Unless you already did, please report this to LTTng. I bet they will be interested in your feedback and maybe also in the fact that they gained another use/test case. Jan --------------enig8DE563DEE852D028EB1081D8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkv5TsYACgkQitSsb3rl5xTxMQCeNL/rjPX+ej58BPK3qM1laSaY JXgAoJJ6aEYKqbHFGfffu7K7fjILzSFT =hfWJ -----END PGP SIGNATURE----- --------------enig8DE563DEE852D028EB1081D8--