From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59224) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UJpFJ-0003Ol-UO for qemu-devel@nongnu.org; Sun, 24 Mar 2013 14:02:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UJpFI-0002mW-S6 for qemu-devel@nongnu.org; Sun, 24 Mar 2013 14:02:17 -0400 Received: from mout.web.de ([212.227.15.4]:61674) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UJpFI-0002mQ-IC for qemu-devel@nongnu.org; Sun, 24 Mar 2013 14:02:16 -0400 Message-ID: <514F3FA5.2050903@web.de> Date: Sun, 24 Mar 2013 19:02:13 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <1361224096-21075-1-git-send-email-aliguori@us.ibm.com> In-Reply-To: <1361224096-21075-1-git-send-email-aliguori@us.ibm.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="----enig2SBEUBMJTUQBLTMCKQBQK" Subject: Re: [Qemu-devel] [PATCH 00/19] chardev flow control List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Amit Shah , Paolo Bonzini , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2SBEUBMJTUQBLTMCKQBQK Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable On 2013-02-18 22:47, Anthony Liguori wrote: > This series implements an idea from Paolo to introduce flow control > in the char layer by converting all char backends to use GIOChannels > internally. Then we can just use the existing IO watch support in glib= > to implement flow control. >=20 > This is based on a rebased version of an old series of mine plus a > number of improvements from Amit Shah. There is a problem with these changes, maybe just a small bug but I do not see a simple solution yet: If an input channel signals readiness but the frontend has no space (can_read returns 0), the main loop will start busy-waiting, causing 100% CPU load. It's trivial to reproduce: qemu-system-x86_64 -serial stdio -S, and then hit a key twice on that console. Jan ------enig2SBEUBMJTUQBLTMCKQBQK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlFPP6UACgkQitSsb3rl5xRqXgCbBScED0WapZOc/pWpx+LfAlQV XpUAnRHnoWp7Aj5FPy4pwmUcSIR7QUPD =CNUI -----END PGP SIGNATURE----- ------enig2SBEUBMJTUQBLTMCKQBQK--