From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=58105 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1OHlTY-0003iE-Ny
	for qemu-devel@nongnu.org; Thu, 27 May 2010 18:22:54 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69)
	(envelope-from <paul@codesourcery.com>) id 1OHlSu-00022A-LE
	for qemu-devel@nongnu.org; Thu, 27 May 2010 18:22:13 -0400
Received: from mail.codesourcery.com ([38.113.113.100]:36502)
	by eggs.gnu.org with esmtp (Exim 4.69)
	(envelope-from <paul@codesourcery.com>) id 1OHlSu-000226-CH
	for qemu-devel@nongnu.org; Thu, 27 May 2010 18:22:12 -0400
From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] Re: [RFT][PATCH 07/15] qemu_irq: Add IRQ handlers
	with delivery feedback
Date: Thu, 27 May 2010 23:21:43 +0100
References: <cover.1274732025.git.jan.kiszka@web.de> <4BFEC322.3030207@web.de>
	<AANLkTimCADl9DW0n_QCqO-3lEHbaZ4oDIiNUAhmgVlA9@mail.gmail.com>
In-Reply-To: <AANLkTimCADl9DW0n_QCqO-3lEHbaZ4oDIiNUAhmgVlA9@mail.gmail.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <201005272321.43949.paul@codesourcery.com>
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: Jan Kiszka <jan.kiszka@web.de>, qemu-devel@nongnu.org, Juan Quintela <quintela@redhat.com>


> >> Then the amount
> >> of CPU cycles between timer interrupts would increase and hopefully
> >> the guest can keep up. If the guest sleeps, time base could be
> >> accelerated to catch up with wall clock and then set back to 1:1 rate.
> > 
> > Can't follow you ATM, sorry. What should be slowed down then? And how
> > precisely?
> 
> I think vm_clock and everything that depends on vm_clock, also
> rtc_clock should be tied to vm_clock in this mode, not host_clock.

The problem is more fundamental than that. There is no real correlation 
between vm_clock and the amount of code executed by the guest, especially not 
on timescales less than a second.

Paul