DOCA Compress

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

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.

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

• DOCA Core Execution Model

• DOCA Core Device

• DOCA Core Memory Subsystem

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 DPU Modes of Operation.

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.

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

Adler and CRC

All compress/decompress tasks produce Adler and CRC.

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

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

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

Buffer Support

Tasks support buffers with the following features:

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

Tasks

Compress Deflate Task

This task facilitates compressing memory using buffers as described in section "Buffer Support".

Configuration

Input

Common input as described in DOCA Core Task.

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 using buffers as described in section "Buffer Support".

Configuration

Input

Common input as described in DOCA Core Task.

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 Task

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

Configuration

Input

Common input as described in DOCA Core Task.

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

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.

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:

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:

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:

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

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

DOCA Compress handles payload only unless the zc flag is used. 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

1. 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.

2. To build a given sample:

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   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/.

3. Sample (e.g., doca_compress_deflate) usage:

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   Usage: doca_compress_deflate [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
     -zc, --zlib-compatible            Write/read a file compatible with default zlib settings
           

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

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   /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:

1. Locating a DOCA device.

2. Initializing the required DOCA core structures.

3. Populating DOCA memory map with two relevant buffers; one for the source data and one for the result.

4. Allocating elements in DOCA buffer inventory for each buffer.

5. Allocating and initializing DOCA Compress deflate task or DOCA Decompress deflate object.

6. Submitting a compress task.

7. Running the progress engine until the task is completed.

8. Writing the result into an output file, out.txt.

9. Destroying all 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

• /opt/mellanox/doca/samples/doca_compress/meson.build