From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:49715)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1VlzUu-0004Tf-0n
	for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:11:09 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1VlzUk-0002Tn-5P
	for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:11:03 -0500
Received: from mx1.redhat.com ([209.132.183.28]:5764)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1VlzUj-0002Ta-TY
	for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:10:54 -0500
Message-ID: <529724B0.80405@redhat.com>
Date: Thu, 28 Nov 2013 12:10:40 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <5294B634.4050801@cloudius-systems.com>
	<20131126150357.GA20352@redhat.com> <5294BC3B.6070902@redhat.com>
	<D3E216785288A145B7BC975F83A2ED10448BBAB3@SZXEMA510-MBS.china.huawei.com>
	<5297050E.6000700@redhat.com> <20131128091903.GA4609@kernel.org>
	<5297118C.3050104@cloudius-systems.com>
	<529712A1.8090207@redhat.com>
	<5297181B.3090109@cloudius-systems.com> <52971D86.60601@redhat.com>
	<20131128110915.GD5822@minantech.com>
In-Reply-To: <20131128110915.GD5822@minantech.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [RFC] create a single workqueue for each vm to
 update vm irq routing table
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: Gleb Natapov <gleb@minantech.com>
Cc: Avi Kivity <avi@cloudius-systems.com>, "Huangweidong (C)" <weidong.huang@huawei.com>, Gleb Natapov <gleb@redhat.com>, KVM <kvm@vger.kernel.org>, "Michael S. Tsirkin" <mst@redhat.com>, "Zhanghaoyu (A)" <haoyu.zhang@huawei.com>, Luonengjun <luonengjun@huawei.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Zanghongyong <zanghongyong@huawei.com>, Avi Kivity <avi.kivity@gmail.com>, "Jinxin (F)" <jinxin712@huawei.com>

Il 28/11/2013 12:09, Gleb Natapov ha scritto:
> > - if there are no callbacks, but there are readers, synchronize_srcu
> > busy-loops for some time checking if the readers complete.  After a
> > while (20 us for synchronize_srcu, 120 us for
> > synchronize_srcu_expedited) it gives up and starts using a workqueue to
> > poll every millisecond.  This should never happen unless
> 
> Unless what ? :) Unless reader is scheduled out?

Yes.  Or unless my brain is scheduled out in the middle of a sentence.

Paolo