From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <virtualization@lists.linux-foundation.org>,
<kvm@vger.kernel.org>, <stefanha@redhat.com>, <oren@nvidia.com>,
<nitzanc@nvidia.com>
Subject: Re: [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file
Date: Mon, 6 Sep 2021 01:21:09 +0300 [thread overview]
Message-ID: <beab43c9-1264-8302-d945-006b4c82e46e@nvidia.com> (raw)
In-Reply-To: <20210905110804-mutt-send-email-mst@kernel.org>
On 9/5/2021 6:09 PM, Michael S. Tsirkin wrote:
> On Sun, Sep 05, 2021 at 03:09:11PM +0300, Max Gurtovoy wrote:
>> For now only add this definition from the spec. In the future, The
>> drivers should negotiate this feature to optimize the performance.
>>
>> Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
> So I think IN_ORDER was a mistake since it breaks ability
> to do pagefaults efficiently without stopping the ring.
I'm not sure I get it.
I wanted to use it for improving performance of a virtio-blk device by
coalescing many completions to one interrupt.
> I think that VIRTIO_F_PARTIAL_ORDER is a better option -
> am working on finalizing that proposal, will post RSN now.
>
>
>> ---
>> include/uapi/linux/virtio_config.h | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
>> index b5eda06f0d57..3fcdc4ab6f19 100644
>> --- a/include/uapi/linux/virtio_config.h
>> +++ b/include/uapi/linux/virtio_config.h
>> @@ -82,6 +82,12 @@
>> /* This feature indicates support for the packed virtqueue layout. */
>> #define VIRTIO_F_RING_PACKED 34
>>
>> +/*
>> + * This feature indicates that all buffers are used by the device in the same
>> + * order in which they have been made available.
>> + */
>> +#define VIRTIO_F_IN_ORDER 35
>> +
>> /*
>> * This feature indicates that memory accesses by the driver and the
>> * device are ordered in a way described by the platform.
>> --
>> 2.18.1
prev parent reply other threads:[~2021-09-05 22:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-05 12:09 [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file Max Gurtovoy
2021-09-05 15:09 ` Michael S. Tsirkin
2021-09-05 22:21 ` Max Gurtovoy [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=beab43c9-1264-8302-d945-006b4c82e46e@nvidia.com \
--to=mgurtovoy@nvidia.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=nitzanc@nvidia.com \
--cc=oren@nvidia.com \
--cc=stefanha@redhat.com \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).