Rivermax (RMAX) Programming Guide

NVIDIA DOCA Rivermax (RMAX) Programming Guide

This guide provides an overview and configuration instructions for the DOCA Rivermax API.

DOCA RMAX is a DOCA API for NVIDIA Rivermax, an optimized networking SDK for media and data streaming applications. Rivermax leverages NVIDIA® BlueField® DPU hardware streaming acceleration technology which enables direct data transfers to and from the GPU, delivering best-in-class throughput and latency with minimal CPU utilization for streaming workloads.

This document is intended for software developers wishing to accelerate their networking operations.

DOCA RMAX-based applications can run on the target DPU. It is recommended to have at least 800 huge pages enabled to achieve maximum performance:

            

            
dpu> echo 1000000000 > /proc/sys/kernel/shmmax
dpu> echo 800 > /proc/sys/vm/nr_hugepages
        

DOCA RMAX library contains two objects:

• doca_rmax_flow – is a flow object that represents an IP/port tuple
• doca_rmax_in_stream – represents the input stream and can be thought of as a receive queue which scatters the received data into memory. Each stream can receive one or more flows.

For the library API reference, refer to DOCA RMAX API documentation in NVIDIA DOCA Libraries API Reference Manual.

The following sections provide additional details about the library API.

4.1. Objects

4.1.1. struct doca_rmax_in_stream

Represents Rivermax's input stream. This is a main object in the RX part.

4.1.2. struct doca_rmax_flow

Represents the steering flow for the input stream to filter incoming data flow by match criteria.

4.2. Library Initialization

Users must explicitly call library initialization and deinitialization functions. Global parameters such as internal thread affinity mask must be set before initialization.

4.2.1. doca_rmax_set_cpu_affinity_mask()

Set the CPU affinity mask for the Rivermax internal thread. This must be called before library initialization. The function doca_rmax_get_cpu_affinity_mask() can be used to query the CPU affinity mask for the Rivermax internal thread at any time.

            

            
doca_error_t doca_rmax_set_cpu_affinity_mask(const struct doca_rmax_cpu_affinity_mask * mask);
        

mask [in]

Affinity mask. The CPU is included in the affinity mask if the corresponding bit is set. By default, affinity mask is not set so the internal thread can run on any CPU core.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.2.2. doca_rmax_init()

This function initializes the DOCA RMAX global resources. This function must be called after doca_rmax_set_cpu_affinity_mask() and before any other DOCA RMAX library call.

            

            
doca_error_t doca_rmax_init(void);
        

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.2.3. doca_rmax_release()

This function cleans up the DOCA RMAX resources. No DOCA RMAX function may be called after calling this function.

            

            
doca_error_t doca_rmax_release(void);
        

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.3. Checking Device Capability

DOCA RMAX can query additional device capabilities related to the library.

4.3.1. doca_rmax_get_ptp_clock_supported()

Query PTP clock capability for device.

            

            
doca_error_t doca_rmax_get_ptp_clock_supported(const struct doca_devinfo * devinfo);
        

devinfo [in]

Device to query

Returns

doca_error_t value

• • DOCA_SUCCESS– PTP clock is supported
  • DOCA_ERROR_NOT_SUPPORTED – PTP clock is not supported
  • Other possible error values are documented in the header file

4.4. Stream Life Cycle

The following sections detail the stages of the stream life cycle from creation to teardown.

4.4.1. Create and Configure Input Stream

4.4.1.1. doca_rmax_in_stream_create()

Create a DOCA RMAX input stream context. The stream can be downcasted to the DOCA context using the function doca_rmax_in_stream_as_ctx().

            

            
doca_error_t doca_rmax_in_stream_create(struct doca_rmax_in_stream ** stream);
        

stream [out]

The input stream context created for the DOCA RMAX. Non-NULL upon success, NULL otherwise.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2. doca_rmax_in_stream_set_*() and doca_rmax_in_stream_get_*()

Use doca_rmax_in_stream_set_*() functions to set the properties of the input stream and the corresponding doca_rmax_in_stream_get_*() functions to retrieve the current properties of the input stream.

4.4.1.2.1. Header-data Split Mode

By default, the DOCA RMAX input stream places the whole packet data into a buffer (memblk_count = 1).

To enable header-data split mode when the headers and payload are placed to a different buffers, set the property memblk_count (doca_rmax_in_stream_set_memblks_count) to 2. In this case you must also set a non-zero value for the min_size/max_size property of memory descriptor (doca_rmax_in_stream_memblk_desc_set_min_size/doca_rmax_in_stream_memblk_desc_set_max_size).

4.4.1.2.1.1. doca_rmax_in_stream_set_memblks_count()

Set the number of configured memory blocks.

            

            
doca_error_t doca_rmax_in_stream_set_memblks_count(struct doca_rmax_in_stream * stream, uint32_t value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.2. Mandatory Properties

4.4.1.2.2.1. doca_rmax_in_stream_set_elements_count()

Set number of elements in the stream buffer. The actual number of elements in a buffer can be increased by the library, so the actual value can be queried using doca_rmax_in_stream_get_elements_count().

            

            
doca_error_t doca_rmax_in_stream_set_elements_count(struct doca_rmax_in_stream * stream, uint32_t value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.2.2. doca_rmax_in_stream_memblk_desc_set_min_size()

Set minimal packet segment size(s). The value is an array of the minimal packet segment sizes received by the input stream.

            

            
doca_error_t doca_rmax_in_stream_memblk_desc_set_min_size(struct doca_rmax_in_stream * stream, uint16_t * value);
        

stream [in]

The input stream to write the property.

value [in]

• When memblk_count=1, pointer to a variable that contains the packet size
• When memblk_count>1, pointer to an array of packet sizes

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.2.3. doca_rmax_in_stream_memblk_desc_set_max_size()

Set maximal packet segment size(s). The value is an array of the maximal packet segment sizes received by the input stream.

            

            
doca_error_t doca_rmax_in_stream_memblk_desc_set_min_size(struct doca_rmax_in_stream * stream, uint16_t * value);
        

stream [in]

The input stream to write the property.

value [in]

• When memblk_count=1, pointer to a variable that contains the packet size
• When memblk_count>1, pointer to an array of packet sizes

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.3. Optional Properties

The following properties have a default value and may be set as long as the input stream is not yet active.

4.4.1.2.3.1. doca_rmax_in_stream_set_type()

Set the input stream type.

            

            
doca_error_t doca_rmax_in_stream_set_type(struct doca_rmax_in_stream * stream, enum doca_rmax_in_stream_type value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.3.2. doca_rmax_in_stream_set_scatter_type()

Set the type of packet's data scatter:

• All packet data including network headers
• Only User-Level Protocol data (discard network header up to L4)
• Payload data only (all headers will be discarded)

            

            
doca_error_t doca_rmax_in_stream_set_scatter_type(struct doca_rmax_in_stream * stream, enum doca_rmax_in_stream_scatter_type value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.3.3. doca_rmax_in_stream_set_timestamp_format()

Set stream timestamp format.

            

            
doca_error_t doca_rmax_in_stream_set_scatter_type(struct doca_rmax_in_stream * stream, enum doca_rmax_in_stream_scatter_type value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.4. Run-time Properties

The following properties have a default value and may be set at any time.

4.4.1.2.4.1. doca_rmax_in_stream_set_min_packets()

Set minimal number of packets that the input stream must return in a read event.

            

            
doca_error_t doca_rmax_in_stream_set_min_packets(struct doca_rmax_in_stream * stream, uint32_t value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.4.2. doca_rmax_in_stream_set_max_packets()

Set the maximal number of packets that the input stream must return in read event.

            

            
doca_error_t doca_rmax_in_stream_set_max_packets(struct doca_rmax_in_stream * stream, uint32_t value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.1.2.4.3. doca_rmax_in_stream_set_timeout_us()

Set receive timeout. The number of μsecs that library would do busy wait (polling) for reception of at least min_packets number of packets.

            

            
doca_error_t doca_rmax_in_stream_set_timeout_us(struct doca_rmax_in_stream * stream, int value);
        

stream [in]

The input stream to write the property.

value [in]

Property value.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.2. Attach Network Device

Attach a network device to the stream context using the doca_ctx_dev_add() function. Only one device per stream is supported.

4.4.3. Query Buffer and Stride Size

Query the memory block size to determine the required size of the memory buffers.

4.4.3.1. doca_rmax_in_stream_get_memblk_size()

Get the size of the memory blocks.

            

            
doca_error_t doca_rmax_in_stream_get_memblk_size(struct doca_rmax_in_stream * stream, size_t * value);
        

stream [in]

The input stream to write the property.

value [out]

Size of the memory block (array of sizes for multiple memblks, the number of memory blocks in stream is more than one).

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.3.2. doca_rmax_in_stream_get_memblk_stride_size()

Get stride sizes.

            

            
doca_error_t doca_rmax_in_stream_get_memblk_stride_size(struct doca_rmax_in_stream * stream, uint16_t * value);
        

stream [in]

The input stream to write the property.

value [out]

Stride size of the memory block (array of stride sizes for multiple memory blocks)

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.4. Create and Set Memory Buffer (doca_buf)

Allocate the memory of at least one previously queried size and then configure the input stream to use this buffer.

For header-data split mode, users must use two buffers and the buffers for the header and the payload data must be chained. See doca_buf_list_chain() for more information.

4.4.4.1. doca_rmax_in_stream_set_memblk()

Set memory buffer(s) to be used as received data storage.

            

            
doca_error_t doca_rmax_in_stream_set_memblk(struct doca_rmax_in_stream * stream, struct doca_buf * buf);
        

stream [in]

The input stream to write the property.

buf [in]

Memory buffer (or head of linked list of memory buffers) to store received data. The length of the linked list must be the same as the number of memory blocks configured.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.5. Start Stream Context

Cast a stream object to the DOCA context and start the context.

4.4.6. Attach to WorkQ

Use the doca_ctx_workq_add() function.

4.4.7. Attach Flows

You can attach one or more flows to a stream after start.

4.4.7.1. doca_rmax_flow_attach()

Attach a flow to a stream.

            

            
doca_error_t doca_rmax_flow_attach (const struct doca_rmax_flow * flow, const struct doca_rmax_in_stream * stream);
        

flow [in]

Flow to operate on.

buf [in]

The context for attaching a flow.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.8. Receive Data

DOCA RMAX does not accept jobs posted to the WorkQ. Instead, you can retrieve available input packets by polling WorkQ progress. Use doca_workq_progress_retrieve() to query available data.

If progress status is DOCA_SUCCESS, then event of type DOCA_RMAX_ACTION_TYPE_RX_DATA contains a pointer to the doca_rmax_in_stream_completion structure in the field of the result.ptr event.

4.4.8.1. doca_rmax_in_stream_completion

Completion is returned by the input stream describing the incoming packets.

            

            
struct doca_rmax_in_stream_completion {
        uint32_t elements_count;
        uint64_t ts_first;
        uint64_t ts_last;
        uint32_t seqn_first;
        uint32_t memblk_ptr_arr_len;
        void **memblk_ptr_arr;
};
        

elements_count

Number of packets received.

ts_first

Time of arrival of the first packet.

ts_last

Time of arrival of the last packet.

seqn_first

Sequence number of the first packet.

memblk_ptr_arr_len

Number of memory blocks placed in memblk_ptr_arr.

memblk_ptr_arr

Array of pointers to the beginning of the memory block as configured by the input stream create step. The offset between packets inside the memory block is a stride size that can be queried using doca_rmax_in_stream_get_memblk_stride_size.

If the progress status is DOCA_ERROR_IO_FAILED, then the event of type DOCA_RMAX_ACTION_TYPE_RX_DATA would contain a pointer to the doca_rmax_stream_error structure in the event's result.ptr field.

4.4.8.2. doca_rmax_stream_error

Detailed completion error information.

            

            
struct doca_rmax_stream_error {
        int code;
        const char *message;
};
        

code

Raw Rivermax error code.

message

Human-readable error message.

Progress status DOCA_ERROR_AGAIN signifies that no data is available yet. All other codes should be handled as a DOCA error.

4.4.9. Teardown

4.4.9.1. Detach Flows

All flows must be detached from an input stream before stopping it.

4.4.9.1.1. doca_rmax_flow_detach()

Detach a flow from a stream.

            

            
doca_error_t doca_rmax_flow_detach (const struct doca_rmax_flow * flow, const struct doca_rmax_in_stream * stream);
        

flow [in]

Flow to operate on.

buf [in]

The context for detaching a flow.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.4.9.2. Detach from WorkQ

Use the doca_ctx_workq_rm() function.

4.4.9.3. Stop Stream Context

Cast the stream object to the DOCA context and stop the context.

4.4.9.4. Detach Network Device

Use the doca_ctx_dev_rm() function.

4.4.9.5. Destroy Stream

4.4.9.5.1. doca_rmax_in_stream_destroy()

Destroy a DOCA input stream context. Free all allocated resources associated with a DOCA RMAX input stream.

            

            
doca_error_t doca_rmax_in_stream_destroy(struct doca_rmax_in_stream * stream);
        

stream [in]

The context to be destroyed.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5. Flow Functions

4.5.1. Create Flow

4.5.1.1. doca_rmax_flow_create()

Create a steering flow for the input stream to filter the incoming data flow by match criteria.

            

            
doca_error_t doca_rmax_flow_create(struct doca_rmax_flow ** flow);
        

flow [out]

The context to be destroyed.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.2. Configure Flow Properties

4.5.2.1. doca_rmax_flow_set_src_ip()

Set the source IP filter for the flow.

            

            
doca_error_t doca_rmax_flow_set_src_ip(struct doca_rmax_flow * flow, const struct in_addr * ip);
        

flow [in]

Flow to operate on.

ip [in]

Source IPv4 address.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.2.2. doca_rmax_flow_set_dst_ip()

Set the destination IP filter for the flow.

            

            
doca_error_t doca_rmax_flow_set_dst_ip(struct doca_rmax_flow * flow, const struct in_addr * ip);
        

flow [in]

Flow to operate on.

ip [in]

Destination IPv4 address.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.2.3. doca_rmax_flow_set_src_port()

Set the source port filter for the flow.

            

            
doca_error_t doca_rmax_flow_set_src_port(struct doca_rmax_flow * flow, uint16_t port);
        

flow [in]

Flow to operate on.

port [in]

Source port number. If zero, then any source port is accepted.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.2.4. doca_rmax_flow_set_dst_port()

Set the destination port filter for the flow.

            

            
doca_error_t doca_rmax_flow_set_dst_port(struct doca_rmax_flow * flow, uint16_t port);
        

flow [in]

Flow to operate on.

port [in]

Destination port number (non-zero)

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.2.5. doca_rmax_flow_set_tag()

Set the tag for the flow.

            

            
doca_error_t doca_rmax_flow_set_tag(struct doca_rmax_flow * flow, uint32_t tag);
        

flow [in]

Flow to operate on.

tag [in]

Non-zero tag

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

4.5.3. Destroy Flow

4.5.3.1. doca_rmax_flow_destroy()

Set the tag for the flow.

            

            
doca_error_t doca_rmax_flow_destroy(struct doca_rmax_flow * flow);
        

flow [in]

Flow to destroy.

Returns

doca_error_t value. DOCA_SUCCESS if successful, or an error value upon failure. Possible error values are documented in the header file.

DOCA RMAX is distributed separately from other DOCA libraries:

• doca-rmax-libs – library binary
• libdoca-rmax-libs-dev – header files and samples

DOCA RMAX binaries depends on:

• doca-runtime
• rivermax

DOCA RMAX headers and samples:

• doca-sdk
• rivermax
• rivermax-ext

Please refer to the for more information about the API of this DOCA library.

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