Hi Ahmed,
> -----Original Message-----
> From: Ahmed Mansour [mailto:ahmed.mans...@nxp.com]
> Sent: Monday, December 18, 2017 9:44 PM
> To: dev@dpdk.org; shally.ve...@cavium.com
> Cc: mahipal.cha...@cavium.com; narayanaprasad.athr...@cavium.com; De Lara
> Guarch, Pablo
> <pablo.de.lara.gua...@intel.com>; Trahe, Fiona <fiona.tr...@intel.com>; Roy
> Pledge
> <roy.ple...@nxp.com>; Youri Querry <youri.querr...@nxp.com>; Hemant Agrawal
> <hemant.agra...@nxp.com>
> Subject: Re: [RFC v3 1/1] lib: add compressdev API
>
> 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
> > + *
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> > + */
> > + RTE_COMP_LZS,
> > + /**< LZS compression algorithm
> > + *
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> > + */
> > + 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?
[Fiona] We've had requests for this from customers.
>
> > +};
> > +
> > +/*
> > + * 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.
[Fiona] We haven't seen a need for those. I would suggest proposing a patch
later once the initial API is stabilised.
> > +};
> > +
> > +/** 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?
[Fiona] Yes, this should be rte_iova_t. will fix this in the v1.
>
> > + 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
[Fiona] It does have the same meaning for compression/decompression?
Just for checksum it's different. Checksum is usually required on the
uncompressed data.
In decompression the input buffer contains compressed data.
> <snip>
> ...
