On Tue, Jan 11, 2022 at 12:01:25PM +0800, Xuan Zhuo wrote:
> This patch allows the driver to obtain some statistics from the device.
>
> In the back-end implementation, we can count a lot of such information,
> which can be used for debugging and judging the running status of the
> back-end. We hope to directly display it to the user through ethtool.
>
> Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
> Reviewed-by: Jason Wang <jasow...@redhat.com>
> ---
>
> v8:
> 1. Modified based on comments by Cornelia Huck
>
> v7:
> 1. add rx_reset, tx_reset
> 2. add device normative and dirver normative
> 3. add comments for *_packets, *_bytres
>
> v6:
> 1. correct the names and descriptions of some stats items
>
> v5:
> 1. add VIRTIO_NET_CTRL_STATS_GET_CTRL_VQ
> 2. more item for virtio_net_ctrl_reply_stats_queue_pair
>
> v4:
> 1. remove dev_stats_num, {rx|tx}_stats_num
> 2. Use two commands to get the stats of queue pair and dev respectively
>
> v3 changes:
> 1. add dev_version
> 2. use queue_pair_index replace rx_num, tx_num
> 3. Explain the processing when the device and driver support different numbers
> of stats
>
> conformance.tex | 2 +
> content.tex | 133 +++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 134 insertions(+), 1 deletion(-)
>
> diff --git a/conformance.tex b/conformance.tex
> index 42f8537..950924e 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -142,6 +142,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> Conformance Targets}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Automatic receive steering in multiqueue mode}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Offloads State Configuration / Setting Offloads State}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Receive-side scaling (RSS) }
> +\item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Device stats}
> \end{itemize}
>
> \conformance{\subsection}{Block Driver Conformance}\label{sec:Conformance /
> Driver Conformance / Block Driver Conformance}
> @@ -401,6 +402,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> Conformance Targets}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Gratuitous Packet Sending}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Automatic receive steering in multiqueue mode}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Receive-side scaling (RSS) / RSS processing}
> +\item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Device stats}
> \end{itemize}
>
> \conformance{\subsection}{Block Device Conformance}\label{sec:Conformance /
> Device Conformance / Block Device Conformance}
> diff --git a/content.tex b/content.tex
> index cf20570..fa385e2 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> Network Device / Feature bits
> \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> channel.
>
> +\item[VIRTIO_NET_F_CTRL_STATS(55)] Device can provide device-level statistics
> + to the driver through the control channel.
> +
> \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets. Unlike UFO
> (fragmenting the packet) the USO splits large UDP packet
> to several segments when each of these smaller packets has UDP header.
> @@ -3137,6 +3140,7 @@ \subsubsection{Feature bit
> requirements}\label{sec:Device Types / Network Device
> \item[VIRTIO_NET_F_GUEST_ANNOUNCE] Requires VIRTIO_NET_F_CTRL_VQ.
> \item[VIRTIO_NET_F_MQ] Requires VIRTIO_NET_F_CTRL_VQ.
> \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> +\item[VIRTIO_NET_F_CTRL_STATS] Requires VIRTIO_NET_F_CTRL_VQ.
> \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> VIRTIO_NET_F_HOST_TSO6.
> \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> \end{description}
> @@ -4015,6 +4019,7 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> Types / Network Device / Devi
> u8 command;
> u8 command-specific-data[];
> u8 ack;
> + u8 command-specific-data-reply[];
> };
>
> /* ack values */
we now need to document which commands include the reply,
otherwise reader will be confused.
> @@ -4023,7 +4028,8 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> Types / Network Device / Devi
> \end{lstlisting}
>
> The \field{class}, \field{command} and command-specific-data are set by the
> -driver, and the device sets the \field{ack} byte. There is little it can
> +driver, and the device sets the \field{ack} byte and optionally
> +\field{command-specific-data-reply}. There is little it can
> do
Now "it" refers to device where it used to refer to the driver.
> except issue a diagnostic if \field{ack} is not
> VIRTIO_NET_OK.
>
> @@ -4471,6 +4477,131 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> Types / Network Device / Devi
> according to the native endian of the guest rather than
> (necessarily when not using the legacy interface) little-endian.
>
> +\paragraph{Device stats}\label{sec:Device Types / Network Device / Device
> Operation / Control Virtqueue / Device stats}
> +
> +If the VIRTIO_NET_F_CTRL_STATS feature is negotiated, the driver can
> +get device stats from the device in \field{command-specific-data-reply}.
> +
> +To get the stats, the following definitions are used:
> +\begin{lstlisting}
> +#define VIRTIO_NET_CTRL_STATS 6
> +#define VIRTIO_NET_CTRL_STATS_GET_DEV 0
> +#define VIRTIO_NET_CTRL_STATS_GET_CTRL_VQ 1
> +#define VIRTIO_NET_CTRL_STATS_GET_QUEUE_PAIR 2
> +\end{lstlisting}
> +
> +The following layout structures are used:
> +
> +\field{command-specific-data}
> +\begin{lstlisting}
> +struct virtio_net_ctrl_stats_queue_pair {
> + le64 queue_pair_index;
> +}
> +\end{lstlisting}
> +
> +\field{command-specific-data-reply}
> +\begin{lstlisting}
> +struct virtio_net_ctrl_reply_stats_dev {
> + le64 dev_reset; // The number of device resets.
while we already have some places using // comments, they
are not used consistently. Better to use /* text */ for now.
> +}
I am still worrying about this one. I think it's a bit vague.
Some types of reset will zero this counter, others will not.
Also, this looks more like a generic capability than anything
specific to net. And this raises questions about .
> +
> +struct virtio_net_ctrl_reply_stats_cvq {
> + le64 request_num; // The number of requests.
We call them commands elsewhere. It is however unclear whether
the request for the stats itself is included in the counter.
Also, do these counters reset on device reset? I would
assume so but given dev_reset does not reset it's hard to be
sure.
> + le64 ok_num; // The number of ok acks.
> + le64 err_num; // The number of err acks.
A bit more precise pls: e.g. "the number of commands where ack was
VIRTIO_NET_OK"?
> +
> + le64 req_rx_promisc; // The number of requests with command
> VIRTIO_NET_CTRL_RX_PROMISC.
> + le64 req_rx_allmulti; // The number of requests with command
> VIRTIO_NET_CTRL_RX_ALLMULTI.
> + le64 req_rx_alluni; // The number of requests with command
> VIRTIO_NET_CTRL_RX_ALLUNI.
> + le64 req_rx_nomulti; // The number of requests with command
> VIRTIO_NET_CTRL_RX_NOMULTI.
> + le64 req_rx_nouni; // The number of requests with command
> VIRTIO_NET_CTRL_RX_NOUNI.
> + le64 req_rx_nobcast; // The number of requests with command
> VIRTIO_NET_CTRL_RX_NOBCAST.
> + le64 req_mac_table_set; // The number of requests with command
> VIRTIO_NET_CTRL_MAC_TABLE_SET.
> + le64 req_mac_addr_set; // The number of requests with command
> VIRTIO_NET_CTRL_MAC_ADDR_SET.
> + le64 req_vlan_add; // The number of requests with command
> VIRTIO_NET_CTRL_VLAN_ADD.
> + le64 req_vlan_del; // The number of requests with command
> VIRTIO_NET_CTRL_VLAN_DEL.
> + le64 req_announce_ack; // The number of requests with command
> VIRTIO_NET_CTRL_ANNOUNCE_ACK.
> + le64 req_mq_vq_pairs_set; // The number of requests with command
> VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET.
> + le64 req_mq_rss_config; // The number of requests with command
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG.
> + le64 req_mq_hash_config; // The number of requests with command
> VIRTIO_NET_CTRL_MQ_HASH_CONFIG.
> + le64 req_guest_offloads_set; // The number of requests with command
> VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET.
> +}
I just had an idea:
how about the query passes in the command we are debugging instead?
this way we do not need to extend this each time.
> +
> +struct virtio_net_ctrl_reply_stats_queue_pair {
> + /* rx stats */
> + le64 rx_packets; // The number of packets recived by device,
> including the dropped packets by device.
> + le64 rx_bytes; // The number of bytes recived by device,
> including the dropped packets by device.
typos: received
> +
> + le64 rx_notification; // The number of notifications from driver.
> + le64 rx_interrupt; // The number of interrupts generated by
> device.
> +
> + le64 rx_drop; // The number of packets dropped by the rx
> queue. Contains all kinds of packet drop.
> + le64 rx_drop_overruns; // The number of packets dropped by the rx
> queue when no more descriptors were available.
> + le64 rx_drop_oversize; // The number of oversized packets received by
> the rx queue.
What does oversized mean in this context? does it apply to
mergeable buffers?
> +
> + le64 rx_csum_valid; // The number of packets with
> VIRTIO_NET_HDR_F_DATA_VALID.
> + le64 rx_csum_partial; // The number of packets with
> VIRTIO_NET_HDR_F_NEEDS_CSUM.
> + le64 rx_csum_bad; // The number of packets with abnormal csum.
> + le64 rx_csum_none; // The number of packets without hardware csum.
I assume they are only incremented with VIRTIO_NET_F_GUEST_CSUM?
> +
> + le64 rx_gso_packets; // The number of gso packets received by rx.
let's spell it out: I think this means any packet
put into VQ and with gso_type != VIRTIO_NET_HDR_GSO_NONE
> + le64 rx_gso_bytes; // The number of gso bytes received by rx.
this one is a bit vague: I assume these are bytes written into the RX VQ
buffers?
the difference is that multiple packets are combined into a
single gso packet.
and does this include the virtio net header?
> + le64 rx_reset; // The number of queue resets.
> +
> + /* tx stats */
> + le64 tx_packets; // The number of packets sent by device,
> excluding the dropped packets by device.
> + le64 tx_bytes; // The number of bytes sent by device,
> excluding the dropped packets by device.
same question: are we talking about bytes sent by device? or
received from guest for transmission?
> +
> + le64 tx_notification; // The number of notifications from driver.
> + le64 tx_interrupt; // The number of interrupts generated by
> device.
> +
> + le64 tx_drop; // The number of packets dropped by the tx
> queue. Contains all kinds of packet drop.
> + le64 tx_drop_desc_err; // The number of packets dropped when the
> descriptor is in an error state.
what is a descriptor in error state?
> +
> + le64 tx_csum_none; // The number of packets that doesn't require
> hardware csum.
> + le64 tx_csum_partial; // The number of packets that requires
> hardware csum.
> +
> + le64 tx_gso_packets; // The number of gso packets transmitted.
> + le64 tx_gso_bytes; // The number of gso bytes transmitted.
point is, gso packets are not transmitted. they are received from
guest. is this what this means? gso bytes probably somehow
means bytes in gso packets, but again this is a bit vague.
> + le64 tx_reset; // The number of queue resets.
queue reset counter sounds like a useful generic capability.
is this with the new features jason added recently?
can we add it to all devices?
> +}
> +\end{lstlisting}
> +
> +All device stats are divided into three categories:
> +\begin{itemize}
> + \item the stats of the device.
> + \begin{itemize}
> + \item command: VIRTIO_NET_CTRL_STATS_GET_DEV
> + \item command-specific-data-reply structure:
> virtio_net_ctrl_reply_stats_dev
> + \end{itemize}
> +
> + \item the stats of the controlq.
> + \begin{itemize}
> + \item command: VIRTIO_NET_CTRL_STATS_GET_CTRL_VQ
> + \item command-specific-data-reply structure:
> virtio_net_ctrl_reply_stats_cvq
> + \end{itemize}
> +
> + \item the stats of the queue pair. This contains the stats of rx and tx.
> + \begin{itemize}
> + \item command: VIRTIO_NET_CTRL_STATS_GET_QUEUE_PAIR
> + \item command-specific-data structure:
> virtio_net_ctrl_stats_queue_pair
> + \item command-specific-data-reply structure:
> virtio_net_ctrl_reply_stats_queue_pair
> + \end{itemize}
> +\end{itemize}
> +
> +\devicenormative{\subparagraph}{Device stats}{Device Types / Network Device
> / Device Operation / Control Virtqueue / Device stats}
> +If \field{queue_pair_index} is out of range for a
> +VIRTIO_NET_CTRL_STATS_GET_QUEUE_PAIR command, the device MUST set
> \field{ack} in
> +virtio_net_ctrl to VIRTIO_NET_ERR.
> +
> +If VIRTIO_NET_F_CTRL_STATS has been negotiated, the device MUST support the
> +VIRTIO_NET_CTRL_STATS_GET_DEV, VIRTIO_NET_CTRL_STATS_GET_CTRL_VQ and
> +VIRTIO_NET_CTRL_STATS_GET_QUEUE_PAIR commands.
> +
> +\drivernormative{\subparagraph}{Device stats}{Device Types / Network Device
> / Device Operation / Control Virtqueue / Device stats}
> +
> +\field{command-specific-data} MUST be empty for VIRTIO_NET_CTRL_STATS_GET_DEV
> +and VIRTIO_NET_CTRL_STATS_GET_CTRL_VQ.
>
> \subsubsection{Legacy Interface: Framing Requirements}\label{sec:Device
> Types / Network Device / Legacy Interface: Framing Requirements}
> --
> 2.31.0
>
>
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