* [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file
@ 2021-09-05 12:09 Max Gurtovoy
2021-09-05 15:09 ` Michael S. Tsirkin
0 siblings, 1 reply; 4+ messages in thread
From: Max Gurtovoy @ 2021-09-05 12:09 UTC (permalink / raw)
To: mst, virtualization, kvm, stefanha; +Cc: oren, nitzanc, Max Gurtovoy
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>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file
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
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2021-09-05 15:09 UTC (permalink / raw)
To: Max Gurtovoy; +Cc: virtualization, kvm, stefanha, oren, nitzanc
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 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file
@ 2021-09-05 15:09 ` Michael S. Tsirkin
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2021-09-05 15:09 UTC (permalink / raw)
To: Max Gurtovoy; +Cc: nitzanc, oren, stefanha, kvm, virtualization
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 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
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] virtio: add VIRTIO_F_IN_ORDER to header file
2021-09-05 15:09 ` Michael S. Tsirkin
(?)
@ 2021-09-05 22:21 ` Max Gurtovoy
-1 siblings, 0 replies; 4+ messages in thread
From: Max Gurtovoy @ 2021-09-05 22:21 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: virtualization, kvm, stefanha, oren, nitzanc
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
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-09-05 22:21 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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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
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