DOCA Compress

This guide provides instructions on how to use the DOCA Compress API.

Introduction

DOCA Compress library provides an API to compress and decompress data using hardware acceleration, supporting both host and NVIDIA® BlueField® DPU memory regions.

The library provides an API for executing compress operations on DOCA buffers, where these buffers reside in either the DPU memory or host memory.

Using DOCA Compress, compress and decompress memory operations can be easily executed in an optimized, hardware-accelerated manner.

This document is intended for software developers wishing to accelerate their application’s compress memory operations.

Prerequisites

The DOCA Compress library follows the architecture of a DOCA Core Context. It is recommended to read the following sections before proceeding:

Environment

DOCA Compress-based applications can run either on the host machine or on the BlueField DPU target.

Compress can only be run with a DPU configured with DPU mode as described in NVIDIA BlueField Modes of Operation.

Architecture

DOCA Compress is a DOCA Context as defined by DOCA Core. See NVIDA DOCA Core Context for more information.

DOCA Compress leverages DOCA Core architecture to expose asynchronous tasks that are offloaded to hardware.

dst-buf-src-buf-version-1-modificationdate-1712750270287-api-v2.png

Supported Compress/Decompress Algorithms

For BlueField-2 devices, this library supports:

Compress operation using the deflate algorithm
Decompress operation using the deflate algorithm

For BlueField-3 devices, this library supports:

Decompress operation using the deflate algorithm
Decompress operation using the LZ4 algorithm

Supported Checksum Methods

Depending on the task type, the following checksum methods are produced and may be retrieved using the relevant getter functions:

Adler – produced by the deflate compress and decompress tasks, as well as the LZ4 decompress task
CRC – produced by all tasks
xxHash – produced by the LZ4 stream and block decompress tasks

Refer to “Tasks” section for more information.

Objects

Device and Device Representor

The library requires a DOCA device to operate, the device is used to access memory and perform the actual copy. See DOCA Core Device Discovery for information.

For same BlueField DPU, it does not matter which device is used (PF/VF/SF), as all these devices utilize the same hardware component. If there are multiple DPUs, it is possible to create a Compress instance per DPU, providing each instance with a device from a different DPU.

To access memory that is not local (from the host to the DPU or vice versa), then the DPU side of the application must pick a device with an appropriate representor. See DOCA Core Device Representor Discovery.

The device must stay valid as long as the Compress instance is not destroyed.

Memory Buffers

All compress/decompress tasks require two DOCA buffers containing the destination and the source. Depending on the allocation pattern of the buffers, refer to the Inventory Types table.

Buffers must not be modified or read during the compress/decompress operation.

Source and Destination Location

DOCA Compress can process DOCA buffers that reside on the host, the DPU, or both.

Local Host

Source and destination buffers reside on the host and the compress library runs on the host.

Local DPU

Source and destination buffers reside on the DPU and the compress library runs on the DPU.

Remote

Source at Host, Destination at DPU

The source resides on the host and is exported (DOCA mmap export) to the DPU
The destination resides on the DPU
The compress library runs on the DPU and compresses/decompresses the host source to the DPU destination

Source at DPU, Destination at Host

The source resides on the DPU
The destination resides on the host and is exported (DOCA mmap export) to the DPU
Compress library runs on the DPU and compresses/decompresses the DPU source to the host destination

Configuration Phase

To start using the library, the user must go through a configuration phase as described in DOCA Core Context Configuration Phase.

This section describes how to configure and start the context, to allow execution of tasks and retrieval of events.

Configurations

The context can be configured to match the use case of the application.

To find if a configuration is supported or what its min/max value is, refer to Device Support.

Mandatory Configurations

The following configurations must be set by the application before attempting to start the context:

At least one task/event type must be configured. See configuration of Tasks.
A device with appropriate support must be provided upon creation

Device Support

DOCA Compress requires a device to operate. To pick a device, see DOCA Core Device Discovery.

As device capabilities may change in the future (see DOCA Core Device Support), it is recommended to select your device using the following APIs:

Supported Tasks

doca_compress_cap_task_compress_deflate_is_supported
doca_compress_cap_task_decompress_deflate_is_supported
doca_compress_cap_task_decompress_lz4_is_supported
doca_compress_cap_task_decompress_lz4_stream_is_supported
doca_compress_cap_task_decompress_lz4_block_is_supported

Supported Buffer Size

doca_compress_cap_task_compress_deflate_get_max_buf_size
doca_compress_cap_task_decompress_deflate_get_max_buf_size
doca_compress_cap_task_decompress_lz4_get_max_buf_size
doca_compress_cap_task_decompress_lz4_stream_get_max_buf_size
doca_compress_cap_task_decompress_lz4_block_get_max_buf_size

Buffer Support

Tasks support buffers with the following features:

Buffer Type	Source Buffer	Destination Buffer
Linked List Buffer	Yes	No
Local mmap Buffer	Yes	Yes
mmap From PCI Export Buffer	Yes	Yes
mmap From RDMA Export Buffer	No	No

Execution Phase

This section describes execution on CPU or DPU using DOCA Core Progress Engine.

Tasks

Compress Deflate Task

This task facilitates compressing memory, with the deflate algorithm, using buffers as described in section “Buffer Support”.

Note

DOCA compress returns only the payload. To create a compressed file, (e.g., gzip), the developer must add a gzip header/trailer.

Configuration

Description	API to set the configuration	API to query support
Enable the task	`doca_compress_task_compress_deflate_set_conf`	`doca_compress_cap_task_compress_deflate_is_supported`
Number of tasks	`doca_compress_task_compress_deflate_set_conf`	`doca_compress_get_max_num_tasks (max total num tasks)`
Maximal buffer size	–	`doca_compress_cap_task_compress_deflate_get_max_buf_size`
Maximum buffer list size	–	`doca_compress_cap_task_compress_deflate_get_max_buf_list_len`

Input

Common input as described in DOCA Core Task.

Name	Description	Notes
Source buffer	Buffer pointing to the memory to be compressed	Only the data residing in the data segment is compressed
Destination buffer	Buffer pointing to where compressed memory will be stored	The data is compressed to the tail segment extending the data segment

Output

Common output as described in DOCA Core Task.

Task Successful Completion

After the task completes successfully, the following happens:

The source data is compressed to destination
The destination buffer data segment is extended to include the compressed data
Adler can be retrieved by calling doca_compress_task_compress_deflate_get_adler_cs
CRC can be retrieved by calling doca_compress_task_compress_deflate_get_crc_cs

Task Failed Completion

If the task fails midway:

The context may enter stopping state if a fatal error occurs
The source and destination doca_buf objects are not modified
The destination buffer contents may be modified

Limitations

The operation is not atomic
Once the task has been submitted, the source and destination should not be read/written to
Source and destination must not overlap
Other limitations are described in DOCA Core Task

Decompress Deflate Task

This task facilitates decompressing memory, with the deflate algorithm, using buffers as described in section “Buffer Support”.

Note

DOCA decompress expects the payload alone. To decompress a file (e.g. gzip), the developer must strip the header/trailer.

Configuration

Description	API to Set the Configuration	API to Query Support
Enable the task	`doca_compress_task_decompress_deflate_set_conf`	`doca_compress_cap_task_decompress_deflate_is_supported`
Number of tasks	`doca_compress_task_decompress_deflate_set_conf`	`doca_compress_get_max_num_tasks (max-total-num-tasks)`
Maximal buffer size	–	`doca_compress_cap_task_decompress_deflate_get_max_buf_size`
Maximum buffer list size	–	`doca_compress_cap_task_decompress_deflate_get_max_buf_list_len`

Input

Common input as described in DOCA Core Task.

Name	Description	Notes
source buffer	Buffer pointing to the memory to be decompressed	Only the data residing in the data segment is decompressed
destination buffer	Buffer pointing to where decompressed memory will be stored	The data is decompressed to the tail segment extending the data segment

Output

Common output as described in DOCA Core Task.

Task Successful Completion

After the task completes successfully, the following happens:

The source data is decompressed to destination
The destination buffer data segment is extended to include the decompressed data
Adler can be retrieved by calling doca_compress_task_decompress_deflate_get_adler_cs
CRC can be retrieved by calling doca_compress_task_decompress_deflate_get_crc_cs

Task Failed Completion

If the task fails midway:

The context may enter stopping state if a fatal error occurs
The source and destination doca_buf objects are not modified
The destination buffer contents may be modified

Limitations

The operation is not atomic
Once the task has been submitted, the source and destination should not be read/written to
Source and destination must not overlap
Other limitations are described in DOCA Core Task

Decompress LZ4 Tasks

These tasks facilitate decompressing memory with the LZ4 algorithm, using buffers as described in section “Buffer Support”, with LZ4.

The main differences between the tasks are:

The input data format –
- The decompress LZ4 task expects the input data to be a full LZ4 frame
- The decompress LZ4 stream task expects a stream of one or more blocks, without the frame (i.e., the magic number, frame descriptor, and content checksum)
- The decompress LZ4 block task expects a single, compressed, data-only block (i.e., without block size or block checksum)
Support for remote buffers – in the decompress LZ4 task, the source buffer must be from local memory, whereas the stream and block tasks do not have this limitation

Decompress LZ4 Task

Note

This task type is deprecated and will be removed in a future DOCA release.

This task facilitates decompressing memory using buffers as described in section “Buffer Support”.

Configuration

Description	API to Set the Configuration	API to Query Support
Enable the task	`doca_compress_task_decompress_lz4_set_conf`	`doca_compress_cap_task_decompress_lz4_is_supported`
Number of tasks	`doca_compress_task_decompress_lz4_set_conf`	`doca_compress_get_max_num_tasks (max total num tasks)`
Maximal buffer size	–	`doca_compress_cap_task_decompress_lz4_get_max_buf_size`
Maximum buffer list size	–	`doca_compress_cap_task_decompress_lz4_get_max_buf_list_len`

Input

Common input as described in DOCA Core Task.

Name	Description	Notes
Source buffer	Buffer pointing to the memory to be decompressed	Only the data residing in the data segment will be decompressed
Destination buffer	Buffer pointing to where decompressed memory will be stored	The data is decompressed to the tail segment extending the data segment

Output

Common output as described in DOCA Core Task.

Task Successful Completion

After the task completes successfully:

The source data is decompressed to destination
The destination buffer data segment is extended to include the decompressed data
Adler can be retrieved by calling doca_compress_task_decompress_lz4_get_adler_cs
CRC can be retrieved by calling doca_compress_task_decompress_lz4_get_crc_cs

Task Failed Completion

If the task fails midway:

The context may enter stopping state if a fatal error occurs
The source and destination doca_buf objects are not modified
The destination buffer contents may be modified

Limitations

The operation is not atomic
Once the task has been submitted, the source and destination should not be read/written to
Source and destination must not overlap
Other limitations are described in DOCA Core Task

Note

This task supports only a source buffer from local memory.

Decompress LZ4 Stream Task

This task facilitates decompressing memory with the LZ4 algorithm, using buffers as described in section “Buffer Support”.

Note

The decompress LZ4 stream task expects a stream of one or more blocks without the frame (i.e., the magic number, frame descriptor, and content checksum).

Configuration

Description	API to Set the Configuration	API to Query Support
Enable the task	`doca_compress_task_decompress_lz4_stream_set_conf`	`doca_compress_cap_task_decompress_lz4_stream_is_supported`
Number of tasks	`doca_compress_task_decompress_lz4_stream_set_conf`	`doca_compress_get_max_num_tasks (max total num tasks)`
Maximal buffer size	–	`doca_compress_cap_task_decompress_lz4_stream_get_max_buf_size`
Maximum buffer list size	–	`doca_compress_cap_task_decompress_lz4_stream_get_max_buf_list_len`

Input

Common input as described in DOCA Core Task.

Name	Description	Notes
Has block checksum Flag	A flag to indicate whether or not the blocks in the stream have a checksum	1 if the task should expect blocks in the stream to have a checksum; 0 otherwise
Are blocks independent flag	A flag to indicate whether or not each block depends on previous blocks in the stream	1 the the task should expect blocks to be independent; 0 otherwise (dependent blocks)
Source buffer	Buffer pointing to the memory to be decompressed	Only the data residing in the data segment is decompressed
Destination buffer	Buffer pointing to where decompressed memory will be stored	The data is decompressed to the tail segment extending the data segment

Output

Common output as described in DOCA Core Task.

Task Successful Completion

After the task completes successfully:

The source data is decompressed to destination
The destination buffer data segment is extended to include the decompressed data
CRC can be retrieved by calling doca_compress_task_decompress_lz4_stream_get_crc_cs
xxHash can be retrieved by calling doca_compress_task_decompress_lz4_stream_get_xxh_cs

Task Failed Completion

If the task fails midway:

The context may enter stopping state if a fatal error occurs
The source and destination doca_buf objects are not modified
The destination buffer contents may be modified

Limitations

The operation is not atomic
Once the task has been submitted, the source and destination should not be read/written to
Source and destination must not overlap
Other limitations are described in DOCA Core Task

Decompress LZ4 Block Task

This task facilitates decompressing memory with the LZ4 algorithm, using buffers as described in section “Buffer Support”.

Note

The decompress LZ4 block task expects a single, compressed, data-only block (i.e., without block size or block checksum).

Configuration

Description	API to Set the Configuration	API to Query Support
Enable the task	`doca_compress_task_decompress_lz4_block_set_conf`	`doca_compress_cap_task_decompress_lz4_block_is_supported`
Number of tasks	`doca_compress_task_decompress_lz4_block_set_conf`	`doca_compress_get_max_num_tasks (max total num tasks)`
Maximal buffer size	–	`doca_compress_cap_task_decompress_lz4_block_get_max_buf_size`
Maximum buffer list size	–	`doca_compress_cap_task_decompress_lz4_block_get_max_buf_list_len`

Input

Common input as described in DOCA Core Task.

Name	Description	Notes
Source buffer	Buffer pointing to the memory to be decompressed	Only the data residing in the data segment will be decompressed
Destination buffer	Buffer pointing to where decompressed memory will be stored	The data is decompressed to the tail segment extending the data segment

Output

Common output as described in DOCA Core Task.

Task Successful Completion

After the task completes successfully:

The source data is decompressed to destination
The destination buffer data segment is extended to include the decompressed data
CRC can be retrieved by calling doca_compress_task_decompress_lz4_block_get_crc_cs
xxHash can be retrieved by calling doca_compress_task_decompress_lz4_bloxk_get_xxh_cs

Task Failed Completion

If the task fails midway:

The context may enter stopping state if a fatal error occurs
The source and destination doca_buf objects are not modified
The destination buffer contents may be modified

Limitations

The operation is not atomic
Once the task has been submitted, the source and destination should not be read/written to
Source and destination must not overlap
Other limitations are described in DOCA Core Task

Events

DOCA Compress exposes asynchronous events to notify about changes that happen unexpectedly according to DOCA Core architecture.

The only events DOCA Compress expose are common events (doca ctx state changed). See more info in DOCA Core Event.

State Machine

The DOCA Compress library follows the Context state machine described in DOCA Core Context State Machine.

This section describes how to move states and what is allowed in each state.

States

Idle

In this state, it is expected that application:

Destroys the context
Starts the context

Allowed operations:

Configuring the context according to Configurations
Starting the context

It is possible to reach this state as follows:

Previous State	Transition Action
None	Create the context
Running	Call stop after making sure all tasks have been freed
Stopping	Call progress until all tasks are completed and freed

Starting

This state cannot be reached.

Running

In this state, it is expected that application:

Allocates and submit tasks
Calls progress to complete tasks and/or receive events

Allowed operations:

Allocate previously configured task
Submit a task
Call stop

It is possible to reach this state as follows:

Previous State	Transition Action
Idle	Call start after configuration

Stopping

In this state, it is expected that application:

Calls progress to complete all inflight tasks (tasks will complete with failure)
Frees any completed tasks

Allowed operations:

Call progress

It is possible to reach this state as follows:

Previous State	Transition Action
Running	Call progress and fatal error occurs
Running	Call stop without freeing all tasks

Alternative Datapath Options

DOCA Compress only supports datapath on CPU, see Execution Phase.

DOCA Compress Samples

The following samples illustrate how to use the DOCA Compress API to compress and decompress files.

Note

DOCA Compress handles payload only unless the zc flag is used (available only for deflate samples). In that case, a zlib header and trailer are added in compression and it is considered as part of the input when decompressing.

Running the Sample

Refer to the following documents:
- NVIDIA DOCA Installation Guide for Linux for details on how to install BlueField-related software.
- NVIDIA DOCA Troubleshooting Guide for any issue you may encounter with the installation, compilation, or execution of DOCA samples.

To build a given sample:

Copy
Copied!

            
            cd /opt/mellanox/doca/samples/doca_compress/<sample_name>
meson /tmp/build
ninja -C /tmp/build

Info

The binary doca_<sample_name> is created under /tmp/build/.

Sample (e.g., doca_compress_deflate) usage:

Common arguments

Copy
Copied!

            
            Usage: doca_<sample_name> [DOCA Flags] [Program Flags]
 
DOCA Flags:
  -h, --help                        Print a help synopsis
  -v, --version                     Print program version information
  -l, --log-level                   Set the (numeric) log level for the program <10=DISABLE, 20=CRITICAL, 30=ERROR, 40=WARNING, 50=INFO, 60=DEBUG, 70=TRACE>
  --sdk-log-level                   Set the SDK (numeric) log level for the program <10=DISABLE, 20=CRITICAL, 30=ERROR, 40=WARNING, 50=INFO, 60=DEBUG, 70=TRACE>
  -j, --json <path>                 Parse all command flags from an input json file
 
Program Flags:
  -p, --pci-addr                    DOCA device PCI device address
  -f, --file                        Input file to compress/decompress
  -o, --output                      Output file
  -c, --output-checksum             Output checksum

Sample-specific arguments

Sample	Argument	Description
Compress/Decompress Deflate	`-zc`, `-zlib-compatible`	Write/read a file compatible with default zlib settings
Decompress LZ4 Stream	`-bc`, `--has-block-checksum`	Flag to indicate if blocks have a checksum
Decompress LZ4 Stream	`-bi`, `--are-blocks-independent`	Flag to indicate if blocks are independent

For additional information per sample, use the -h option:

Copy
Copied!

            
            /tmp/build/doca_<sample_name> -h

Samples

Compress/Decompress Deflate

This sample illustrates how to use DOCA Compress library to compress or decompress a file.

The sample logic includes:

Locating a DOCA device.
Initializing the required DOCA Core structures.
Populating DOCA memory map with two relevant buffers; one for the source data and one for the result.
Allocating elements in DOCA buffer inventory for each buffer.
Allocating and initializing a DOCA Compress deflate task or a DOCA Decompress deflate task.
Submitting the task.
Running the progress engine until the task is completed.
Writing the result into an output file, out.txt.
Destroying all DOCA Compress and DOCA Core structures.

References:

/opt/mellanox/doca/samples/doca_compress/compress_deflate/compress_deflate_sample.c
/opt/mellanox/doca/samples/doca_compress/compress_deflate/compress_deflate_main.c
/opt/mellanox/doca/samples/doca_compress/compress_deflate/meson.build
/opt/mellanox/doca/samples/doca_compress/decompress_deflate/decompress_deflate_sample.c
/opt/mellanox/doca/samples/doca_compress/decompress_deflate/decompress_deflate_main.c
/opt/mellanox/doca/samples/doca_compress/decompress_deflate/meson.build
/opt/mellanox/doca/samples/doca_compress/compress_common.h
/opt/mellanox/doca/samples/doca_compress/compress_common.c

Decompress LZ4 Stream

This sample illustrates how to use DOCA Compress library to decompress a file using the LZ4 stream decompress task.

The sample logic includes:

Locating a DOCA device.
Initializing the required DOCA Core structures.
Populating DOCA memory map with two relevant buffers; one for the source data and one for the result.
Allocating elements in DOCA buffer inventory for each buffer.
Allocating and initializing an DOCA Decompress LZ4 stream task.
Submitting the task.
Running the progress engine until the task is completed.
Writing the result into an output file, out.txt.
Destroying all DOCA Compress and DOCA Core structures.

References:

/opt/mellanox/doca/samples/doca_compress/decompress_lz4_stream/decompress_lz4_stream_sample.c
/opt/mellanox/doca/samples/doca_compress/decompress_lz4_stream/decompress_lz4_stream_main.c
/opt/mellanox/doca/samples/doca_compress/decompress_lz4_stream/meson.build
/opt/mellanox/doca/samples/doca_compress/compress_common.h
/opt/mellanox/doca/samples/doca_compress/compress_common.c

Backward Compatibility

Decompress LZ4 Task

The d ecompress LZ4 task is deprecated, and will be removed in a future release. It is recommended to use the decompress LZ4 stream task or the decompress LZ4 block task instead.

On This Page