From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH 00/15] xen/tools: add tracing to various Xen subsystems Date: Thu, 8 Jun 2017 18:45:57 +0200 Message-ID: <1496940357.26212.2.camel@citrix.com> References: <149633614204.12814.14390287626133023934.stgit@Solace.fritz.box> <20170607141343.GB32578@char.us.oracle.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0036843184124328274==" Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dJ0ZY-0002cn-5g for xen-devel@lists.xenproject.org; Thu, 08 Jun 2017 16:46:12 +0000 In-Reply-To: <20170607141343.GB32578@char.us.oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Konrad Rzeszutek Wilk Cc: Stefano Stabellini , Wei Liu , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Jan Beulich , Jennifer Herbert , xen-devel@lists.xenproject.org, Doug Goldstein List-Id: xen-devel@lists.xenproject.org --===============0036843184124328274== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="=-T3e617/hfMtRLY1HGXqf" --=-T3e617/hfMtRLY1HGXqf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2017-06-07 at 10:13 -0400, Konrad Rzeszutek Wilk wrote: > On Thu, Jun 01, 2017 at 07:33:33PM +0200, Dario Faggioli wrote: > >=20 > > Patch 5 deserves special mention. In fact, now that we have > > Kconfig, I thought > > it could be a nice thing to make it possible to select, at build > > config time, > > whether we want tracing or not, in the hypervisor (like, for > > instance, we do > > for performance counters). >=20 > Did you have thoughts on perhaps using asm goto as an > alterantive to unlikely? >=20 > In Linux it is called jump labels or such - the idea is that the=C2=A0 > code has (by default and on x86) five NOP instructions. But you > can patch it over and add an call to the unlikely code. >=20 Yes, I know. I've never actually looked at the code, but I know they do that, and I think it's cool. > But perhaps that is more of an future idea as looking at the Linux > code > it looks quite large and not that simple. >=20 I would love for us to do something similar in Xen. I've _thought_ about that many times, but that's it. :-/ Let's see... right now, I can't look into this, as I agree with you that it would be a major piece of work. But yes, it's been in my thoughts! :-) Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-T3e617/hfMtRLY1HGXqf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJZOX9FAAoJEBZCeImluHPubT0QAMBGP8z8AHR26DuX2Tv4cT6y NWFTZw8kVytHiQqww+6O5iodUje+/vqXBzgaATkinrFe21Z3jD9+KUchuFPbukmE v0HDLpim+5JDq1w5SZyj+9bje5Vc8Q9LgBg75yfsotS7ij57KCaZi1J9s0DvtLol nEkJR8a7nMDS2ICXg2HfPKnhOo3hKBYDV/hXnMAttJYexxXM9QidUse8Dbi1D1ni lDxVD/ftCznBKBc5SueCRQFK4B7FRYYh2vY6tTe6Wx6SrOlyGbfc9ucSWT354xJJ /RANNaYpt/iMnjz+PZRAu88pcYtZIQ3Z/9CGBJXVylHyWEl9MxUS+Yw4VVv6ym7h BrfMjIagaX3k3d/DyanTZObdvA1tKY1/lFSNM73LvxiAudHcJ1jFAkVggk0zJEDx AVrPYqFY3rgq9w57Z4i+P+RBdFFHwTZVSj7IEq6vfn4vtxM2iLIQz5WrLmxo9Eo7 VVhY/HomHxIJ6XuSb6OyfUKQrhOcT1YrPoD903dxmC3jHbgVlPrV1s5fySGCyKOy vLUqdgukF46j8lcnY6iVUd4UmYWSCFa9O6xfHPOed3jiZhSuyblWugUKFriC+8at iu1XjUoQEE9Sc2MRZtrTiZ84sbasLd6xzC2HBNTl5o1e0QatQM2y80Rqs1Sa/aBs kvCoGgblttmDe6R/wgOf =rOpF -----END PGP SIGNATURE----- --=-T3e617/hfMtRLY1HGXqf-- --===============0036843184124328274== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVs IG1haWxpbmcgbGlzdApYZW4tZGV2ZWxAbGlzdHMueGVuLm9yZwpodHRwczovL2xpc3RzLnhlbi5v cmcveGVuLWRldmVsCg== --===============0036843184124328274==--