From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JkxDV-0002po-8n for qemu-devel@nongnu.org; Sun, 13 Apr 2008 04:05:37 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JkxDU-0002pE-5L for qemu-devel@nongnu.org; Sun, 13 Apr 2008 04:05:36 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JkxDT-0002p7-UD for qemu-devel@nongnu.org; Sun, 13 Apr 2008 04:05:36 -0400 Received: from fmmailgate03.web.de ([217.72.192.234]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1JkxDT-0005v2-Aq for qemu-devel@nongnu.org; Sun, 13 Apr 2008 04:05:35 -0400 Message-ID: <4801BECA.1040303@web.de> Date: Sun, 13 Apr 2008 10:05:30 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] 8250: more realistic TX-done IRQ rate References: <4800CDAE.3090606@web.de> <200804121748.06132.paul@codesourcery.com> <4800ED38.1080003@web.de> In-Reply-To: <4800ED38.1080003@web.de> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB65678BA87E7E6C3C1C0A3EB" 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: qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB65678BA87E7E6C3C1C0A3EB Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Jan Kiszka wrote: > Paul Brook wrote: >> On Saturday 12 April 2008, Jan Kiszka wrote: >> I'd also expect you to have the same problem with the RX queue. If you= >> don't it's a bug elsewhere in qemu. >> >>> + qemu_mod_timer(s->tx_timer, 1000 / (11520 / s->divider))= ; >> >> This looks bogus. I think you're a few orders of magnitude out in your= >> timing calculations. As mentioned above, in practice you unlikely to >> get anywhere >> near the necessary realtime performance out of qemu. >=20 > That depends. Current Linux distros typically have > CONFIG_HIGH_RES_TIMERS enabled. But, of course, not many OSes QEMU work= s > on have such support at all, and even Linux may decided to work without= > it for various reasons. OK, that line was totally bogus. Somehow I once assumed that qemu_mod_timer takes relative timeout (though I've used it with absolute dates before). A new version will follow soon, which in fact triggered a second patch for another issue of the current emulation - the hard-coded baudbase. Jan --------------enigB65678BA87E7E6C3C1C0A3EB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFIAb7NniDOoMHTA+kRAnaoAJ43rCfEzQAr40Zm2/k9FxfUUXUiLQCbBVEw /iO/ifIdLVY1j2wPv0pFRHU= =Kb5f -----END PGP SIGNATURE----- --------------enigB65678BA87E7E6C3C1C0A3EB--