From: Avi Kivity <avi@cloudius-systems.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>,
qemu-devel@nongnu.org, liuyongan@huawei.com,
qinchuanyu@huawei.com, "Zhangjie (HZ)" <zhangjie14@huawei.com>,
akong@redhat.com
Subject: Re: [Qemu-devel] [QA-virtio]:Why vring size is limited to 1024?
Date: Wed, 08 Oct 2014 14:00:38 +0300 [thread overview]
Message-ID: <54351956.9030909@cloudius-systems.com> (raw)
In-Reply-To: <20141008105515.GA4429@redhat.com>
On 10/08/2014 01:55 PM, Michael S. Tsirkin wrote:
>
>> Inline descriptors will amortize the cache miss over 4 descriptors, and will
>> allow the hardware to prefetch, since the descriptors are linear in memory.
> If descriptors are used in order (as they are with current qemu)
> then aren't they amortized already?
>
The descriptors are only in-order for non-zero-copy net. They are out
of order for block and zero-copy net.
(also, the guest has to be careful in how it allocates descriptors).
prev parent reply other threads:[~2014-10-08 11:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-30 8:36 [Qemu-devel] [QA-virtio]:Why vring size is limited to 1024? Zhangjie (HZ)
2014-09-30 9:33 ` Michael S. Tsirkin
2014-10-08 7:17 ` Zhangjie (HZ)
2014-10-08 7:37 ` Michael S. Tsirkin
2014-10-08 8:07 ` Zhangjie (HZ)
2014-10-08 9:13 ` Michael S. Tsirkin
2014-10-08 7:43 ` Avi Kivity
2014-10-08 8:26 ` Zhangjie (HZ)
2014-10-08 9:15 ` Michael S. Tsirkin
2014-10-08 9:51 ` Avi Kivity
2014-10-08 10:14 ` Michael S. Tsirkin
2014-10-08 10:37 ` Avi Kivity
2014-10-08 10:55 ` Michael S. Tsirkin
2014-10-08 10:59 ` Avi Kivity
2014-10-08 12:22 ` Michael S. Tsirkin
2014-10-08 12:28 ` Avi Kivity
2014-10-08 12:36 ` Avi Kivity
2014-10-08 11:00 ` Avi Kivity [this message]
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