From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48150) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cQcx6-0002lX-UA for qemu-devel@nongnu.org; Mon, 09 Jan 2017 11:37:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cQcx6-0002Oh-0k for qemu-devel@nongnu.org; Mon, 09 Jan 2017 11:37:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46490) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cQcx5-0002OH-Qk for qemu-devel@nongnu.org; Mon, 09 Jan 2017 11:37:43 -0500 Date: Mon, 9 Jan 2017 16:28:47 +0000 From: Stefan Hajnoczi Message-ID: <20170109162847.GI30228@stefanha-x1.localdomain> References: <148278447806.8988.12706825771606357198.stgit@fimbulvetr.bsc.es> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="sl5MdczEF/OU2Miu" Content-Disposition: inline In-Reply-To: <148278447806.8988.12706825771606357198.stgit@fimbulvetr.bsc.es> Subject: Re: [Qemu-devel] [PATCH v4 0/6] hypertrace: Lightweight guest-to-QEMU trace channel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Llu=EDs?= Vilanova Cc: qemu-devel@nongnu.org, Daniel P Berrange , Luiz Capitulino , Eric Blake --sl5MdczEF/OU2Miu Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Dec 26, 2016 at 09:34:38PM +0100, Llu=EDs Vilanova wrote: > The hypertrace channel allows guest code to emit events in QEMU (the host= ) using > its tracing infrastructure (see "docs/trace.txt"). This works in both 'sy= stem' > and 'user' modes, is architecture-agnostic and introduces minimal noise o= n the > guest. >=20 > See first commit for a full description, use-cases and an example. As mentioned previously, the -system mode "1 vmexit per trace event" approach is too heavyweight for for performance analysis or high frequency tracing. It might be useful for things like system bringup or TCG development though. The -user approach is more promising because overheads are lower when guest code really just jumps into QEMU code. I have left comments on the patches. --sl5MdczEF/OU2Miu Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJYc7o/AAoJEJykq7OBq3PI74MIALtS30W5IrL+OaavQwT1oWI+ hRG2Ldvlsoml7eO9ehz34AVTZotdyJFdnQcatQjVVDTbDg6kFKls61UI9rcs82oB PjID0l/i0PWsW2YSs0l0Ps3Ld06v3nN17v14phAc1JF+cMybahk/5RBaH8BTqRBW bXFdbdUMKZLImFdgzIkYK4L8dPwPGjtf5Aw4jIuBNg7aye+w1Eoij+zxqnMYQd+G thAZaLffPEsZ1DK1n+z+15QfW3ETYR3rJZCfDW4Byc7+8rTDqj7pnmiFiTGZIFGy kMFsAWnlfoVT0W1F5aN5uj6c2M6LYrFjKi39kRFcFg2xrTF87DDuaToAjt9uREA= =3WiX -----END PGP SIGNATURE----- --sl5MdczEF/OU2Miu--