From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=41354 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1PsaFX-0004mU-5S
	for qemu-devel@nongnu.org; Thu, 24 Feb 2011 07:24:52 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <quintela@redhat.com>) id 1PsaFV-0007WA-S6
	for qemu-devel@nongnu.org; Thu, 24 Feb 2011 07:24:51 -0500
Received: from mx1.redhat.com ([209.132.183.28]:32674)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <quintela@redhat.com>) id 1PsaFV-0007W0-Hy
	for qemu-devel@nongnu.org; Thu, 24 Feb 2011 07:24:49 -0500
From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <AANLkTimF+YMYVNjP2W_ryQ_f7CDgZW_B1jupNAT2ONyx@mail.gmail.com>
	(Yoshiaki Tamura's message of "Thu, 24 Feb 2011 13:19:48 +0900")
References: <cover.1298421307.git.quintela@redhat.com>
	<83ec39769be88d8e9916e2180830765c722eebaa.1298421307.git.quintela@redhat.com>
	<AANLkTinqSO-6y5y9m839Ry==ksnfPoLfFuhCuda0h_bj@mail.gmail.com>
	<m34o7v85se.fsf@trasno.org>
	<AANLkTimF+YMYVNjP2W_ryQ_f7CDgZW_B1jupNAT2ONyx@mail.gmail.com>
Date: Thu, 24 Feb 2011 13:23:19 +0100
Message-ID: <m3hbbt39l4.fsf@trasno.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: [Qemu-devel] Re: [PATCH 22/22] migration: Make state definitions
	local
Reply-To: quintela@redhat.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: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Cc: qemu-devel@nongnu.org

Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp> wrote:
> 2011/2/23 Juan Quintela <quintela@redhat.com>:
>> Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp> wrote:
>>> 2011/2/23 Juan Quintela <quintela@redhat.com>:

>>> Although you're right, I would prefer to keep it so that somebody
>>> outside of migration may understand the status in the future if
>>> there are no harms.
>>
>> my plan is to move MigrationState inside migration.c, and then decide
>> what to export/not export.
>
> Well, it may be just a policy, but it's already exported, and I
> would like to keep it unless it bothers your plan.  IIUC, I don't
> think it does.
>
>> Next thing to do is move migration to its
>> own thread. =C2=A0Before doing that, I need to know what parts are used/=
not
>> used outside migration.c. =C2=A0Removing it now means that nothing gets =
to
>> use it without needing a patch.
>
> I've once asked Anthony whether it's possible to make migration
> to different threads, but his answer was no due to hard
> dependency of qemu's internal code, and making migration to
> different threads are bad design.

I know.  But Anthony is seeing the light O:-)

Basically, without an own thread we are not able to:
- do anything else while on incoming migration
  (namely using the monitor)
- do anything else than migration.  We can try hard and let vcpus to
  run, but we would still clog the io_thread.
- We are not able to saturate 10Gbit networking (basically we are doing
  2/3 level of bufferering (depending on how you count).

So, once code is there, I guess we will convince Anthony to commit it.

Later, Juan.