From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [RFC PATCH 21/24] ARM: vITS: handle INVALL command Date: Fri, 9 Dec 2016 11:14:14 +0100 Message-ID: <1481278454.3445.199.camel@citrix.com> References: <20160928182457.12433-1-andre.przywara@arm.com> <0fce93d4-605b-78b9-9146-b4d65eb4e86a@arm.com> <4a8bb842-bac5-942f-ca84-d223f43ab50b@arm.com> <1481059976.3445.98.camel@citrix.com> <1481063995.3445.125.camel@citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0293848280246995091==" Return-path: Received: from mail6.bemta6.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cFIC8-0005uz-IW for xen-devel@lists.xenproject.org; Fri, 09 Dec 2016 10:14:24 +0000 In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Stefano Stabellini Cc: Vijay Kilari , Steve Capper , Andre Przywara , george.dunlap@citrix.com, Julien Grall , xen-devel List-Id: xen-devel@lists.xenproject.org --===============0293848280246995091== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="=-Yavy3TufA5ncsU2FI0iQ" --=-Yavy3TufA5ncsU2FI0iQ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2016-12-07 at 12:21 -0800, Stefano Stabellini wrote: > On Tue, 6 Dec 2016, Dario Faggioli wrote: > > E.g., if I have pCPU 0 loaded at 75% and pCPU 1 loaded at 25%, vCPU > > A > > has a lot of routed interrupts, and moving it gives me perfect load > > balancing (i.e., load will become 50% on pCPU 0 and 50% on pCPU 1) > > should I move it or not? > > Well, it depends if whether or not we think that the overhead we > > save > > by not migrating outweights the benefit of a perfectly balanced > > system. >=20 > Right. I don't know where to draw the line. I don't how much weight > it > should have, but certainly it shouldn't be considered the same thing > as > moving any other vCPU. > Right. As I said, Credit2 load balancer is nice and easy to extend already --and needs to become nicer and easier to extend in order to deal with soft-affinity, so I'll work on that soon (there's patches out for soft-affinity which does sort of something like that, but I'm not entirely satisfied of them, so I'll probably rework that part). At that point, I'll be more than happy to consider this, and try to reason about how much it should be weighted. After all, the only thing we need to take this information into account when making load balancing decisions is a mechanism for knowing how many of these routed interrupt a vCPU has, and of course this needs to be: =C2=A0- easy to use, =C2=A0- super quick (load balancing is an hot path), =C2=A0- architecture independent, is this the case already? :-) Thanks and Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-Yavy3TufA5ncsU2FI0iQ 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 iQIcBAABCAAGBQJYSoP2AAoJEBZCeImluHPu36kQAMRdXdHzgKHkf6M262vklT7y 06CL4/ok/6gzRde/74Y17HHt2y9dGns7/OE+9lKVK1O+cqeK5KYiwt8vYwEZEY5f MjIoHcPdnoNDKqxiTnJCzYMr6RK23LLNpxsRB1SV7qz8ZRf0Ih5DlQ7rIJ1uc1h5 Z3AisEamjSx8UrkiuQtKPnvZRJhpRO2mmQvL78sHbprN64lQBnNKPZOfTafQJLwN 8xXkLZyAUjheVdoMXk4/MZeIXKOlUrC3xBjNbsBusQVDn3fgewK0HDdlXLtyTNlz 5HOJkCJXb+MpatTmiBnFD1PQ+9LnKJ6qxv5WqzxlDDDbN2Z1h6XU31qUFSf1OukQ CDgv51reOcXIDQemxl8lsY2Kl/dT5MRXob3vHIlhybu5ey+YpA8K+AFZL76FsnDd fbJ7c8T84y5LzWmR5cSm/acNXMbTbE2AIinnewFhIG4mpTEPX9nYK1q8+LmAwmjG V9uONsPRLuLbga9tYTq6StiIftZnRrg7Md/LyihNsLn9NsH/yLZC0RV8UQdy7wWK lkBNdvJTFQJ+Wtbr3DyK3fTv1iSJbM/sliAi3aKVt8VKw4wvLjXEqnRCLQxwHwXu 4BSD54OJmp6fLXHtpHKCINcsJT4FRvep+uQA37kfnVE3Um/fQrkoh7F8I0hrLRjs /ZMTQ4c4hedX4qwZYYQC =6QlI -----END PGP SIGNATURE----- --=-Yavy3TufA5ncsU2FI0iQ-- --===============0293848280246995091== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVs IG1haWxpbmcgbGlzdApYZW4tZGV2ZWxAbGlzdHMueGVuLm9yZwpodHRwczovL2xpc3RzLnhlbi5v cmcveGVuLWRldmVsCg== --===============0293848280246995091==--