Re: [dpdk-dev] [RFC v3 1/1] lib: add compressdev API

[Ahmed Mansour <ahmed.mansour@nxp.com>]

On 12/15/2017 11:19 PM, Trahe, Fiona wrote:
.. <snip>

> +
> +/** Compression Algorithms */
> +enum rte_comp_algorithm {
> +	RTE_COMP_NULL = 0,
> +	/**< No compression.
> +	 * Pass-through, data is copied unchanged from source buffer to
> +	 * destination buffer.
> +	 */
> +	RTE_COMP_DEFLATE,
> +	/**< DEFLATE compression algorithm
> +	 * https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftools.ietf.org%2Fhtml%2Frfc1951&data=02%7C01%7Cahmed.mansour%40nxp.com%7Cf3edbd70b38b49eb1f0308d54634e444%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636492115333128845&sdata=B3G0aIncVAK17dXlnSivXi0e56h2D7pEQZ9gK%2Fh3qZQ%3D&reserved=0
> +	 */
> +	RTE_COMP_LZS,
> +	/**< LZS compression algorithm
> +	 * https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftools.ietf.org%2Fhtml%2Frfc2395&data=02%7C01%7Cahmed.mansour%40nxp.com%7Cf3edbd70b38b49eb1f0308d54634e444%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636492115333128845&sdata=aNRFIfkelXlCUUgpp%2BzCYaTu28tp6fF0m6k7F13w1Ps%3D&reserved=0
> +	 */
> +	RTE_COMP_ALGO_LIST_END
> +};
> +
> +/**< Compression Level.
> + * The number is interpreted by each PMD differently. However, lower numbers
> + * give fastest compression, at the expense of compression ratio while
> + * higher numbers may give better compression ratios but are likely slower.
> + */
> +#define	RTE_COMP_LEVEL_PMD_DEFAULT	(-1)
> +/** Use PMD Default */
> +#define	RTE_COMP_LEVEL_NONE		(0)
> +/** Output uncompressed blocks if supported by the specified algorithm */
> +#define RTE_COMP_LEVEL_MIN		(1)
> +/** Use minimum compression level supported by the PMD */
> +#define RTE_COMP_LEVEL_MAX		(9)
> +/** Use maximum compression level supported by the PMD */
> +
> +/** Compression checksum types */
> +enum rte_comp_checksum_type {
> +	RTE_COMP_NONE,
> +	/**< No checksum generated */
> +	RTE_COMP_CRC32,
> +	/**< Generates a CRC32 checksum, as used by gzip */
> +	RTE_COMP_ADLER32,
> +	/**< Generates an Adler-32 checksum, as used by zlib */
> +	RTE_COMP_CRC32_ADLER32,
> +	/**< Generates both Adler-32 and CRC32 checksums, concatenated.
> +	 * CRC32 is in the lower 32bits, Adler-32 in the upper 32 bits.
> +	 */

What would be a real life use case for returning both CRC32 and ADLER32?
Packaging the data once as Gzip and once as zlib?

> +};
> +
> +/*
> + * enum rte_comp_hash_algo {
> + *   RTE_COMP_HASH_NONE,
> + *   RTE_COMP_HASH_SHA1,
> + *   RTE_COMP_HASH_SHA256,
> + * };
> + * Need further input from cavium on this
> + * xform will need a flag with above enum value
> + * op will need to provide a virt/phys ptr to a data buffer of appropriate size.
> + * And via capability PMD can say whether supported or not.
> + */
> +
> +/** Compression Huffman Type - used by DEFLATE algorithm */
> +enum rte_comp_huffman {
> +	RTE_COMP_DEFAULT,
> +	/**< PMD may choose which Huffman codes to use */
> +	RTE_COMP_FIXED,
> +	/**< Use Fixed Huffman codes */
> +	RTE_COMP_DYNAMIC,
> +	/**< Use Dynamic Huffman codes */
> +};
> +
> +
> +enum rte_comp_flush_flag {
> +	RTE_COMP_FLUSH_NONE,
> +	/**< Data is not flushed. Output may remain in the compressor and be
> +	 * processed during a following op. It may not be possible to decompress
> +	 * output until a later op with some other flush flag has been sent.
> +	 */
> +	RTE_COMP_FLUSH_SYNC,
> +	/**< All data should be flushed to output buffer. Output data can be
> +	 * decompressed. However state and history is not cleared, so future
> +	 * ops may use history from this op */
> +	RTE_COMP_FLUSH_FULL,
> +	/**< All data should be flushed to output buffer. Output data can be
> +	 * decompressed. State and history data is cleared, so future
> +	 * ops will be independent of ops processed before this.
> +	 */
> +	RTE_COMP_FLUSH_FINAL
> +	/**< Same as RTE_COMP_FLUSH_FULL but also bfinal bit is set in last block
> +	 */
> +	 /* TODO:
> +	  * describe flag meanings for decompression.
> +	  * describe behavous in OUT_OF_SPACE case.
> +	  * At least the last flag is specific to deflate algo. Should this be
> +	  * called rte_comp_deflate_flush_flag? And should there be
> +	  * comp_op_deflate_params in the op? */

What about Z_BLOCK and Z_TREES? Those are needed for sfwr zlib.net 
replacements.

> +};
> +
> +/** Compression transform types */
> +enum rte_comp_xform_type {
> +	RTE_COMP_COMPRESS,
> +	/**< Compression service - compress */
> +	RTE_COMP_DECOMPRESS,
> +	/**< Compression service - decompress */
> +};
> +

... <snip>

> +struct rte_comp_session;
> +/**
> + * Compression Operation.
> + *
> + * This structure contains data relating to performing a compression
> + * operation on the referenced mbuf data buffers.
> + *
> + * All compression operations are Out-of-place (OOP) operations,
> + * as the size of the output data is different to the size of the input data.
> + *
> + * Comp operations are enqueued and dequeued in comp PMDs using the
> + * rte_compressdev_enqueue_burst() / rte_compressdev_dequeue_burst() APIs
> + */
> +struct rte_comp_op {
> +
> +	enum rte_comp_op_type op_type;
> +	void * stream_private;
> +	/* location where PMD maintains stream state
> +	 * only required if op_type is STATEFUL, else should be NULL
> +	 */
> +	struct rte_comp_session *session;
> +	/**< Handle for the initialised session context */
> +	struct rte_mempool *mempool;
> +	/**< mempool from which operation is allocated */
> +	phys_addr_t phys_addr;
> +	/**< physical address of this operation */

iova_addr?

> +	struct rte_mbuf *m_src;
> +	/**< source mbuf
> +	 * The total size of the input buffer(s) can be retrieved using
> +	 * rte_pktmbuf_data_len(m_src)
> +	 */
> +	struct rte_mbuf *m_dst;
> +	/**< destination mbuf
> +	 * The total size of the output buffer(s) can be retrieved using
> +	 * rte_pktmbuf_data_len(m_dst)
> +	 */
> +
> +	struct {
> +		uint32_t offset;
> +		/**< Starting point for compression or decompression,
> +		 * specified as number of bytes from start of packet in
> +		 * source buffer.
> +		 * Starting point for checksum generation in compress direction.
> +		 */

Why should offset have two different meanings for compression and
decompression. It seems that the use case of offset on input is
applicable to both use modes

<snip>
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