[dpdk-dev,v4,4/5] hash: rte_hash_crc() slices data into 8-byte pieces
Commit Message
Calculating hash for data of variable length is more efficient
when that data is sliced into 8-byte pieces. The rest part of data
is hashed using CRC32 functions with either 8 and 4 byte operands.
Signed-off-by: Yerden Zhumabekov <e_zhumabekov@sts.kz>
---
lib/librte_hash/rte_hash_crc.h | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)
@@ -445,7 +445,7 @@ rte_hash_crc_8byte(uint64_t data, uint32_t init_val)
}
/**
- * Use crc32 instruction to perform a hash.
+ * Calculate CRC32 hash on user-supplied byte array.
*
* @param data
* Data to perform hash on.
@@ -460,23 +460,38 @@ static inline uint32_t
rte_hash_crc(const void *data, uint32_t data_len, uint32_t init_val)
{
unsigned i;
- uint32_t temp = 0;
- const uint32_t *p32 = (const uint32_t *)data;
+ uint64_t temp = 0;
+ const uint64_t *p64 = (const uint64_t *)data;
- for (i = 0; i < data_len / 4; i++) {
- init_val = rte_hash_crc_4byte(*p32++, init_val);
+ for (i = 0; i < data_len / 8; i++) {
+ init_val = rte_hash_crc_8byte(*p64++, init_val);
}
- switch (3 - (data_len & 0x03)) {
+ switch (7 - (data_len & 0x07)) {
case 0:
- temp |= *((const uint8_t *)p32 + 2) << 16;
+ temp |= (uint64_t) *((const uint8_t *)p64 + 6) << 48;
/* Fallthrough */
case 1:
- temp |= *((const uint8_t *)p32 + 1) << 8;
+ temp |= (uint64_t) *((const uint8_t *)p64 + 5) << 40;
/* Fallthrough */
case 2:
- temp |= *((const uint8_t *)p32);
+ temp |= (uint64_t) *((const uint8_t *)p64 + 4) << 32;
+ temp |= *((const uint32_t *)p64);
+ init_val = rte_hash_crc_8byte(temp, init_val);
+ break;
+ case 3:
+ init_val = rte_hash_crc_4byte(*(const uint32_t *)p64, init_val);
+ break;
+ case 4:
+ temp |= *((const uint8_t *)p64 + 2) << 16;
+ /* Fallthrough */
+ case 5:
+ temp |= *((const uint8_t *)p64 + 1) << 8;
+ /* Fallthrough */
+ case 6:
+ temp |= *((const uint8_t *)p64);
init_val = rte_hash_crc_4byte(temp, init_val);
+ /* Fallthrough */
default:
break;
}