From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:39720)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <borntraeger@de.ibm.com>) id 1Z2kvQ-0006yC-3y
	for qemu-devel@nongnu.org; Wed, 10 Jun 2015 14:40:33 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <borntraeger@de.ibm.com>) id 1Z2kvL-0005md-U3
	for qemu-devel@nongnu.org; Wed, 10 Jun 2015 14:40:32 -0400
Received: from e06smtp11.uk.ibm.com ([195.75.94.107]:60620)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <borntraeger@de.ibm.com>) id 1Z2kvL-0005mG-Jf
	for qemu-devel@nongnu.org; Wed, 10 Jun 2015 14:40:27 -0400
Received: from /spool/local
	by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use
	Only! Violators will be prosecuted
	for <qemu-devel@nongnu.org> from <borntraeger@de.ibm.com>;
	Wed, 10 Jun 2015 19:40:26 +0100
Message-ID: <55788495.1050902@de.ibm.com>
Date: Wed, 10 Jun 2015 20:40:21 +0200
From: Christian Borntraeger <borntraeger@de.ibm.com>
MIME-Version: 1.0
References: <1433936297-7098-1-git-send-email-yarygin@linux.vnet.ibm.com>
In-Reply-To: <1433936297-7098-1-git-send-email-yarygin@linux.vnet.ibm.com>
Content-Type: text/plain; charset=iso-8859-15
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH RFC v2 0/3] Fix slow startup with many disks
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/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: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Alexander Yarygin <yarygin@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-block@nongnu.org, Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>, Stefan Hajnoczi <stefanha@redhat.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>

Am 10.06.2015 um 13:38 schrieb Alexander Yarygin:
> Changes in v2:
>     - Patch "block-backend: Introduce blk_drain() and replace blk_drain_all()"
>       splitted to two.
>     - blk_drain() moved to above virtio_blk_data_plane_stop().
> 
> During reset the aio_poll() function is called at least amount_of_disks^2 times:
> 
> for_each disk
>     virtio_blk_reset()
>         bdrv_drain_all()
>                 for_each disk
>                          aio_poll()
> 
> For example, startup with 1000 disks takes over 13 minutes.
> 
> Patches 1 and 2 removes inner loop by using bdrv_drain() instead
> of bdrv_drain_all(). bdrv_drain() works on one disk at time.
> 
> Since bdrv_drain_all() is still called in other places, patch 3 optimizes
> it for cases, where there are more disks than iothreads.
> 
> Thanks.
> 
> Alexander Yarygin (3):
>   block-backend: Introduce blk_drain()
>   virtio-blk: Use blk_drain() to drain IO requests
>   block: Let bdrv_drain_all() to call aio_poll() for each AioContext
> 
>  block/block-backend.c          |  5 +++++
>  block/io.c                     | 42 ++++++++++++++++++++++++++----------------
>  hw/block/virtio-blk.c          | 11 ++++++-----
>  include/sysemu/block-backend.h |  1 +
>  4 files changed, 38 insertions(+), 21 deletions(-)
> 

Whole series is 
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>

I think we can remove the RFC. I would like to see this for 2.4.

Christian