From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KD4kH-0000xi-Iu for qemu-devel@nongnu.org; Sun, 29 Jun 2008 17:47:41 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KD4kF-0000xW-6K for qemu-devel@nongnu.org; Sun, 29 Jun 2008 17:47:40 -0400 Received: from [199.232.76.173] (port=40629 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KD4kF-0000xT-0f for qemu-devel@nongnu.org; Sun, 29 Jun 2008 17:47:39 -0400 Received: from fmmailgate01.web.de ([217.72.192.221]:44860) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KD4kE-00060E-T0 for qemu-devel@nongnu.org; Sun, 29 Jun 2008 17:47:39 -0400 Message-ID: <486802EE.40100@web.de> Date: Sun, 29 Jun 2008 23:47:26 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH 1/3] Change qemu_set_irq() to return status information. References: <20080629140120.5626.1590.stgit@gleb-debian.qumranet.com.qumranet.com> <200806292134.08436.paul@codesourcery.com> <4867F786.7070002@web.de> <200806292216.10253.paul@codesourcery.com> In-Reply-To: <200806292216.10253.paul@codesourcery.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig39F2306B68BCA82EB5F0C83A" Sender: jan.kiszka@web.de Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paul Brook Cc: Gleb Natapov , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig39F2306B68BCA82EB5F0C83A Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Paul Brook wrote: > On Sunday 29 June 2008, Jan Kiszka wrote: >> Paul Brook wrote: >>>> The model takes into account that not all interrupt controller are >>>> capable to detect missed interrupt (it is possible that there is no >>>> interrupt controller at all). In this case irq function should >>>> return one and everything will fall back to how it works now. >>> On a related note the correct way to fix this is "-icount auto". >>> You should make sure that your hacks are not enabled when we have a >>> realistic virtual timebase. >> Virtual timebases don't help if the guest has to interact with the rea= l >> life - ie. clocks you cannot tweak. In the end, you will have to bring= =20 >> them in sync again, so this approach basically points in the right >> direction. >=20 > That's exactly what -icount auto does. It gradually varies the virtual = clock=20 > rate to keep it in line with the outside world. You get some clock skew= , but=20 > that true whatever you do (including the proposed patch). Interesting. This seems to require a closer look, and maybe some quantification of the potential overhead. Jan --------------enig39F2306B68BCA82EB5F0C83A 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 iEYEARECAAYFAkhoAvgACgkQniDOoMHTA+kjNACfR/rxucPpd9Xt4XhCYhToaJgd fT8Ania7PPLhTtR95Vi12wjsKlUJi87U =bynf -----END PGP SIGNATURE----- --------------enig39F2306B68BCA82EB5F0C83A--