From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=41793 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Ogh9P-0005XY-3i
	for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:49:08 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69)
	(envelope-from <avi@redhat.com>) id 1Ogh9N-0005RQ-RH
	for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:49:06 -0400
Received: from mx1.redhat.com ([209.132.183.28]:40771)
	by eggs.gnu.org with esmtp (Exim 4.69)
	(envelope-from <avi@redhat.com>) id 1Ogh9N-0005RJ-K2
	for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:49:05 -0400
Message-ID: <4C5999FA.5060100@redhat.com>
Date: Wed, 04 Aug 2010 19:48:58 +0300
From: Avi Kivity <avi@redhat.com>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with
	Linux 2.6.35?
References: <4C5854F1.3000905@codemonkey.ws> <4C5858B2.9090801@redhat.com>
	<4C585F5B.5070502@codemonkey.ws> <4C58635B.7020407@redhat.com>
	<4C597E6D.1040609@cisco.com> <4C597FCD.8070703@codemonkey.ws>
	<20100804152552.GB10499@redhat.com>
	<D254D65D-8E8D-482B-8527-6E987AD6D738@suse.de>
	<20100804154830.GC10499@redhat.com>
	<3935DA5C-1FE5-4289-AB99-29FAA7B62580@suse.de>
	<20100804160823.GE10499@redhat.com>
In-Reply-To: <20100804160823.GE10499@redhat.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
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: Gleb Natapov <gleb@redhat.com>
Cc: Alexander Graf <agraf@suse.de>, kvm@vger.kernel.org, qemu-devel@nongnu.org, "Richard W.M. Jones" <rjones@redhat.com>, "David S. Ahern" <daahern@cisco.com>

  On 08/04/2010 07:08 PM, Gleb Natapov wrote:
>
> After applying cache fix nothing definite as far as I remember (I ran it last time
> almost 2 week ago, need to rerun). Code always go through emulator now
> and check direction flags to update SI/DI accordingly. Emulator is a big
> switch and it calls various callbacks that may also slow things down.
>

We can have it set up a fast path.  Similar to how real hardware 
optimizes 'rep movs' to copy complete cachelines.

The emulator does all the checks, sets up a callback to be called on 
completion or when an interrupt is made pending, and lets x86.c do all 
the work.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.