All of lore.kernel.org
 help / color / mirror / Atom feed
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

      reply	other threads:[~2021-09-05 22:21 UTC|newest]

Thread overview: 4+ 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 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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.