From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D0BC398644C for ; Tue, 28 Sep 2021 03:25:57 +0000 (UTC) MIME-Version: 1.0 References: <1632724210.6422126-1-xuanzhuo@linux.alibaba.com> In-Reply-To: <1632724210.6422126-1-xuanzhuo@linux.alibaba.com> From: Jason Wang Date: Tue, 28 Sep 2021 11:25:40 +0800 Message-ID: Subject: [virtio-dev] Re: [PATCH v3] virtio-net: support device stats Content-Type: text/plain; charset="UTF-8" To: Xuan Zhuo Cc: Virtio-Dev List-ID: On Mon, Sep 27, 2021 at 2:54 PM Xuan Zhuo wrote: > > On Mon, 27 Sep 2021 11:50:35 +0800, Jason Wang wrote: > > On Thu, Sep 16, 2021 at 5:33 PM 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 > > > --- > > > > > > 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 > > > > > > content.tex | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 115 insertions(+) > > > > > > diff --git a/content.tex b/content.tex > > > index 7cec1c3..2e45a55 100644 > > > --- a/content.tex > > > +++ b/content.tex > > > @@ -2972,6 +2972,9 @@ \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. > > > @@ -3017,6 +3020,7 @@ \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} > > > @@ -3895,6 +3899,7 @@ \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 */ > > > @@ -3906,6 +3911,9 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi > > > driver, and the device sets the \field{ack} byte. There is little it can > > > do except issue a diagnostic if \field{ack} is not > > > VIRTIO_NET_OK. > > > +\field{command-specific-data-reply} is alloced by driver, then pass to device. > > > +It is filled by the device. It is optional. Some commands need to get some > > > +information from the device. > > > > Let's just reuse the "sets" as above. > > > > E.g "and the device set the \field{ack} and optionally > > \field{command-specific-data-reply}" > > OK. > > > > > > > > > \paragraph{Packet Receive Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering} > > > \label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting Promiscuous Mode}%old label for latexdiff > > > @@ -4384,6 +4392,113 @@ \subsubsection{Legacy Interface: Framing Requirements}\label{sec:Device > > > See \ref{sec:Basic > > > Facilities of a Virtio Device / Virtqueues / Message Framing}. > > > > > > +\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 by \field{command-specific-data-reply}. > > > + > > > +\subparagraph{Device stats keys}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Device stats keys / Device stats keys} > > > + > > > +The keys of the device stats are defined as follows. When the device fills in > > > +\field{command-specific-data-reply}, it MUST be written in the following order. > > > +Subsequent newly added keys MUST be added at the end of each category. > > > +These keys will eventually be shown to the user. > > > + > > > +All stats are divided into three categories: > > > + > > > +\begin{itemize} > > > + \item dev stats: the stats of the device > > > + \begin{itemize} > > > + \item dev_version: The number of device version. > > > + \item dev_reset: The number of device reset. > > > + \end{itemize} > > > + > > > + \item rx stats: the stats of the rx queue > > > + \begin{itemize} > > > + \item rx[N]_inter: The number of interrupts sent by the rx queue. > > > + \item rx[N]_drop: The number of packets dropped by the rx queue. Contains all kinds of packet loss. > > > + \item rx[N]_drop_overruns: The number of packets dropped by the rx queue when no more avail desc. > > > + \item rx[N]_csum_bad: The number of packets with abnormal csum in the rx queue. > > > + \item rx[N]_gso_packets: The number of gso packets received by rx. > > > + \item rx[N]_gso_bytes: The number of gso bytes received by rx. > > > + \item rx[N]_oversize_pkts: The number of oversized packets received by the rx queue. > > > + \end{itemize} > > > + > > > + \item tx stats: the stats of the tx queue > > > + \begin{itemize} > > > + \item tx[N]_inter: The number of interrupts sent by the tx queue. > > > + \item tx[N]_drop: The number of packets dropped by the tx queue. Contains all kinds of packet loss. > > > + \item tx[N]_csum: The number of packets that completes csum by the device. > > > + \item tx[N]_gso_packets: The number of gso packets transmitted. > > > + \item tx[N]_gso_bytes: The number of gso bytes transmitted. > > > + \end{itemize} > > > +\end{itemize} > > > > Let's use C stcture for this. > > The main purpose here is to define the order of these keys. > > This issue will be discussed below. > > > > > > > + > > > +\subparagraph{Device stats get}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Device stats keys / Device stats get} > > > + > > > +To get the stats, the following definitions are used: > > > +\begin{lstlisting} > > > +#define VIRTIO_NET_CTRL_STATS 6 > > > +#define VIRTIO_NET_CTRL_STATS_GET 0 > > > +\end{lstlisting} > > > + > > > +The following layout structure are used: > > > + > > > +\field{command-specific-data} > > > +\begin{lstlisting} > > > +le64 queue_pair_index > > > +le64 dev_stats_num; > > > +le64 rx_stats_num; > > > +le64 tx_stats_num; > > > +\end{lstlisting} > > > + > > > +\field{command-specific-data-reply} > > > +\begin{lstlisting} > > > +le64 queue_pair_index > > > +le64 dev_stats_num; > > > +le64 rx_stats_num; > > > +le64 tx_stats_num; > > > +le64 dev_stats[dev_stats_num]; > > > +le64 rx_stats[rx_stats_num]; > > > +le64 tx_stats[tx_stats_num]; > > > +\end{lstlisting} > > > + > > > +The command VIRTIO_NET_CTRL_STATS_GET is used to obtain this information. > > > + > > > +Regarding the variables in \field{command-specific-data}: > > > +\begin{itemize} > > > + \item \field{queue_pair_index}: Specify the queue pair index of the queue that the driver wants to get stats. > > > + \item \field{dev_stats_num}: Indicates the number of dev stats supported by the driver. > > > + \item \field{rx_stats_num}: Indicates the number of stats information the driver wants for rx queue. > > > + \item \field{tx_stats_num}: Indicates the number of stats information the driver wants for tx queue. > > > > We have feature negotiation mechanism, so I think we don't need > > dev_stats_num, {rx|tx}_stats_num here. Instead, all of those should be > > inferred from the features. > > The feature just indicates that the driver can obtain status information from > the device. But with the development, it is difficult for the device and the > driver to support the new key synchronously. The feature is also difficult to > sense how many new keys the driver and the device support respectively. So I think the feature works fine for this. VIRTIO_NET_F_CTRL_STATS -> stats set A VIRTIO_NET_F_CTRL_STATS_X -> stats set A + stats set X ... The point is to unbreak the migration. We don't want to surprise the user if some of the keys were added or deleted after migration. > > For example, there are currently only two dev_stats, and both the device and the > driver only support two keys. If the virtio spec adds a new dev stats, the > driver may first support three keys, but the device still supports only two. The > number of keys supported by both parties is needed to negotiate. So let's say VIRTIO_NET_F_CTRL_STATS (two keys) but VIRTIO_NET_F_CTRL_STATS_X has three keys. In this case if VIRTIO_NET_F_CTRL_STATS_X is not supported by the device (only two keys), it won't be negotiated and the driver knows the device will only return 2 keys. > > dev_stats_num, (rx|tx)_stats_num exists for this purpose. > > I think the increase of these keys is a relatively frequent thing. Probably not, looking at other NIC drivers the "keys" are pretty stable. We can start from a large set anyhow. Thanks > It is also > difficult to synchronize the support for new keys between drivers and devices. > > Thanks. > > > > > > Thanks > > > > > +\end{itemize} > > > + > > > +Regarding the variables in \field{command-specific-data-reply}: > > > +\begin{itemize} > > > + \item All variables of \field{command-specific-data-reply} are set by the device. > > > + \item \field{queue_pair_index} MUST be equal to the variable with the same name in \field{command-specific-data}. > > > + \item These variables(\field{dev_stats_num}, \field{rx_stats_num}, \field{tx_stats_num}) MUST be > > > + less than or equal to the variables with the same name in \field{command-specific-data}. > > > + These values indicate the amount of stats actually filled in. > > > + \item \field{command-specific-data-reply} is meaningful only when \field{ack} is equal to VIRTIO_NET_OK. > > > +\end{itemize} > > > + > > > +The variables \field{dev_stats_num}, \field{rx_stats_num}, \field{tx_stats_num} in \field{command-specific-data} > > > +specify which stats the driver wants to get, but in fact the device may support > > > +more or fewer stats. > > > + > > > +If the actual number of stats supported by the device is equal to or less than > > > +the number that the driver wants to obtain, then the device MUST write all the > > > +stats to the corresponding position of \field{command-specific-data-reply}. > > > + > > > +And if the number of stats actually supported by the device is more than the > > > +driver requires, then the device MUST only write the number supported by the > > > +driver. > > > + > > > +If the some of the variables \field{dev_stats_num}, \field{rx_stats_num}, \field{tx_stats_num} in \field{command-specific-data} are 0, > > > +that means that the driver does not want to obtain this type of stats, > > > +then the device MUST set the same name field in \field{command-specific-data-reply} to 0, and skip this type of stats. > > > + > > > \section{Block Device}\label{sec:Device Types / Block Device} > > > > > > The virtio block device is a simple virtual block device (ie. > > > -- > > > 2.31.0 > > > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org