From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
qemu-devel@nongnu.org
Subject: Re: [PATCHv2-RFC 0/2] virtio: put last seen used index into ring itself
Date: Mon, 31 May 2010 17:16:42 +0930 [thread overview]
Message-ID: <201005311716.43573.rusty@rustcorp.com.au> (raw)
In-Reply-To: <cover.1274903328.git.mst@redhat.com>
On Thu, 27 May 2010 05:20:35 am Michael S. Tsirkin wrote:
> Here's a rewrite of the original patch with a new layout.
> I haven't tested it yet so no idea how this performs, but
> I think this addresses the cache bounce issue raised by Avi.
> Posting for early flames/comments.
Sorry, not without some evidence that it'll actually reduce cacheline
bouncing. I *think* it will, but it's not obvious: the host may keep
looking at avail_idx as we're updating last_seen. Or does qemu always
look at both together anyway?
Can someone convince me this is a win?
Rusty.
WARNING: multiple messages have this Message-ID (diff)
From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: [Qemu-devel] Re: [PATCHv2-RFC 0/2] virtio: put last seen used index into ring itself
Date: Mon, 31 May 2010 17:16:42 +0930 [thread overview]
Message-ID: <201005311716.43573.rusty@rustcorp.com.au> (raw)
In-Reply-To: <cover.1274903328.git.mst@redhat.com>
On Thu, 27 May 2010 05:20:35 am Michael S. Tsirkin wrote:
> Here's a rewrite of the original patch with a new layout.
> I haven't tested it yet so no idea how this performs, but
> I think this addresses the cache bounce issue raised by Avi.
> Posting for early flames/comments.
Sorry, not without some evidence that it'll actually reduce cacheline
bouncing. I *think* it will, but it's not obvious: the host may keep
looking at avail_idx as we're updating last_seen. Or does qemu always
look at both together anyway?
Can someone convince me this is a win?
Rusty.
next prev parent reply other threads:[~2010-05-31 7:46 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-26 19:50 [PATCHv2-RFC 0/2] virtio: put last seen used index into ring itself Michael S. Tsirkin
2010-05-26 19:50 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-26 19:50 ` [PATCHv2-RFC 1/2] virtio: support layout with avail ring before idx Michael S. Tsirkin
2010-05-26 19:50 ` Michael S. Tsirkin
2010-05-26 19:50 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-26 19:50 ` [PATCHv2-RFC 2/2] virtio: publish used idx Michael S. Tsirkin
2010-05-26 19:50 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-26 19:50 ` Michael S. Tsirkin
2010-05-27 12:07 ` [PATCHv2-RFC 0/2] virtio: put last seen used index into ring itself Avi Kivity
2010-05-27 12:07 ` [Qemu-devel] " Avi Kivity
2010-05-27 13:59 ` Michael S. Tsirkin
2010-05-27 13:59 ` Michael S. Tsirkin
2010-05-27 13:59 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-27 12:07 ` Avi Kivity
2010-05-28 9:56 ` Jes Sorensen
2010-05-28 9:56 ` Jes Sorensen
2010-05-28 9:56 ` [Qemu-devel] " Jes Sorensen
2010-05-30 11:22 ` Michael S. Tsirkin
2010-05-30 11:22 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-31 7:36 ` Jes Sorensen
2010-05-31 7:36 ` Jes Sorensen
2010-05-31 7:36 ` [Qemu-devel] " Jes Sorensen
2010-05-31 13:29 ` Michael S. Tsirkin
2010-05-31 13:29 ` Michael S. Tsirkin
2010-05-31 13:29 ` [Qemu-devel] " Michael S. Tsirkin
2010-05-30 11:22 ` Michael S. Tsirkin
2010-05-31 7:46 ` Rusty Russell [this message]
2010-05-31 7:46 ` [Qemu-devel] " Rusty Russell
2010-05-31 12:20 ` Michael S. Tsirkin
2010-05-31 12:20 ` Michael S. Tsirkin
2010-05-31 12:20 ` [Qemu-devel] " Michael S. Tsirkin
2010-06-02 20:39 ` Jes Sorensen
2010-06-02 20:39 ` Jes Sorensen
2010-06-02 20:39 ` Jes Sorensen
2010-05-31 7:46 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2010-05-26 19:50 Michael S. Tsirkin
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