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Diffstat (limited to 'lib/librte_sched/rte_bitmap.h')
| -rw-r--r-- | lib/librte_sched/rte_bitmap.h | 560 |
1 files changed, 560 insertions, 0 deletions
diff --git a/lib/librte_sched/rte_bitmap.h b/lib/librte_sched/rte_bitmap.h new file mode 100644 index 00000000..ff675c58 --- /dev/null +++ b/lib/librte_sched/rte_bitmap.h @@ -0,0 +1,560 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef __INCLUDE_RTE_BITMAP_H__ +#define __INCLUDE_RTE_BITMAP_H__ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @file + * RTE Bitmap + * + * The bitmap component provides a mechanism to manage large arrays of bits + * through bit get/set/clear and bit array scan operations. + * + * The bitmap scan operation is optimized for 64-bit CPUs using 64/128 byte cache + * lines. The bitmap is hierarchically organized using two arrays (array1 and + * array2), with each bit in array1 being associated with a full cache line + * (512/1024 bits) of bitmap bits, which are stored in array2: the bit in array1 + * is set only when there is at least one bit set within its associated array2 + * bits, otherwise the bit in array1 is cleared. The read and write operations + * for array1 and array2 are always done in slabs of 64 bits. + * + * This bitmap is not thread safe. For lock free operation on a specific bitmap + * instance, a single writer thread performing bit set/clear operations is + * allowed, only the writer thread can do bitmap scan operations, while there + * can be several reader threads performing bit get operations in parallel with + * the writer thread. When the use of locking primitives is acceptable, the + * serialization of the bit set/clear and bitmap scan operations needs to be + * enforced by the caller, while the bit get operation does not require locking + * the bitmap. + * + ***/ + +#include <rte_common.h> +#include <rte_debug.h> +#include <rte_memory.h> +#include <rte_branch_prediction.h> +#include <rte_prefetch.h> + +#ifndef RTE_BITMAP_OPTIMIZATIONS +#define RTE_BITMAP_OPTIMIZATIONS 1 +#endif + +/* Slab */ +#define RTE_BITMAP_SLAB_BIT_SIZE 64 +#define RTE_BITMAP_SLAB_BIT_SIZE_LOG2 6 +#define RTE_BITMAP_SLAB_BIT_MASK (RTE_BITMAP_SLAB_BIT_SIZE - 1) + +/* Cache line (CL) */ +#define RTE_BITMAP_CL_BIT_SIZE (RTE_CACHE_LINE_SIZE * 8) +#define RTE_BITMAP_CL_BIT_SIZE_LOG2 (RTE_CACHE_LINE_SIZE_LOG2 + 3) +#define RTE_BITMAP_CL_BIT_MASK (RTE_BITMAP_CL_BIT_SIZE - 1) + +#define RTE_BITMAP_CL_SLAB_SIZE (RTE_BITMAP_CL_BIT_SIZE / RTE_BITMAP_SLAB_BIT_SIZE) +#define RTE_BITMAP_CL_SLAB_SIZE_LOG2 (RTE_BITMAP_CL_BIT_SIZE_LOG2 - RTE_BITMAP_SLAB_BIT_SIZE_LOG2) +#define RTE_BITMAP_CL_SLAB_MASK (RTE_BITMAP_CL_SLAB_SIZE - 1) + +/** Bitmap data structure */ +struct rte_bitmap { + /* Context for array1 and array2 */ + uint64_t *array1; /**< Bitmap array1 */ + uint64_t *array2; /**< Bitmap array2 */ + uint32_t array1_size; /**< Number of 64-bit slabs in array1 that are actually used */ + uint32_t array2_size; /**< Number of 64-bit slabs in array2 */ + + /* Context for the "scan next" operation */ + uint32_t index1; /**< Bitmap scan: Index of current array1 slab */ + uint32_t offset1; /**< Bitmap scan: Offset of current bit within current array1 slab */ + uint32_t index2; /**< Bitmap scan: Index of current array2 slab */ + uint32_t go2; /**< Bitmap scan: Go/stop condition for current array2 cache line */ + + /* Storage space for array1 and array2 */ + uint8_t memory[0]; +}; + +static inline void +__rte_bitmap_index1_inc(struct rte_bitmap *bmp) +{ + bmp->index1 = (bmp->index1 + 1) & (bmp->array1_size - 1); +} + +static inline uint64_t +__rte_bitmap_mask1_get(struct rte_bitmap *bmp) +{ + return (~1lu) << bmp->offset1; +} + +static inline void +__rte_bitmap_index2_set(struct rte_bitmap *bmp) +{ + bmp->index2 = (((bmp->index1 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2) + bmp->offset1) << RTE_BITMAP_CL_SLAB_SIZE_LOG2); +} + +#if RTE_BITMAP_OPTIMIZATIONS + +static inline int +rte_bsf64(uint64_t slab, uint32_t *pos) +{ + if (likely(slab == 0)) { + return 0; + } + + *pos = __builtin_ctzll(slab); + return 1; +} + +#else + +static inline int +rte_bsf64(uint64_t slab, uint32_t *pos) +{ + uint64_t mask; + uint32_t i; + + if (likely(slab == 0)) { + return 0; + } + + for (i = 0, mask = 1; i < RTE_BITMAP_SLAB_BIT_SIZE; i ++, mask <<= 1) { + if (unlikely(slab & mask)) { + *pos = i; + return 1; + } + } + + return 0; +} + +#endif + +static inline uint32_t +__rte_bitmap_get_memory_footprint(uint32_t n_bits, + uint32_t *array1_byte_offset, uint32_t *array1_slabs, + uint32_t *array2_byte_offset, uint32_t *array2_slabs) +{ + uint32_t n_slabs_context, n_slabs_array1, n_cache_lines_context_and_array1; + uint32_t n_cache_lines_array2; + uint32_t n_bytes_total; + + n_cache_lines_array2 = (n_bits + RTE_BITMAP_CL_BIT_SIZE - 1) / RTE_BITMAP_CL_BIT_SIZE; + n_slabs_array1 = (n_cache_lines_array2 + RTE_BITMAP_SLAB_BIT_SIZE - 1) / RTE_BITMAP_SLAB_BIT_SIZE; + n_slabs_array1 = rte_align32pow2(n_slabs_array1); + n_slabs_context = (sizeof(struct rte_bitmap) + (RTE_BITMAP_SLAB_BIT_SIZE / 8) - 1) / (RTE_BITMAP_SLAB_BIT_SIZE / 8); + n_cache_lines_context_and_array1 = (n_slabs_context + n_slabs_array1 + RTE_BITMAP_CL_SLAB_SIZE - 1) / RTE_BITMAP_CL_SLAB_SIZE; + n_bytes_total = (n_cache_lines_context_and_array1 + n_cache_lines_array2) * RTE_CACHE_LINE_SIZE; + + if (array1_byte_offset) { + *array1_byte_offset = n_slabs_context * (RTE_BITMAP_SLAB_BIT_SIZE / 8); + } + if (array1_slabs) { + *array1_slabs = n_slabs_array1; + } + if (array2_byte_offset) { + *array2_byte_offset = n_cache_lines_context_and_array1 * RTE_CACHE_LINE_SIZE; + } + if (array2_slabs) { + *array2_slabs = n_cache_lines_array2 * RTE_BITMAP_CL_SLAB_SIZE; + } + + return n_bytes_total; +} + +static inline void +__rte_bitmap_scan_init(struct rte_bitmap *bmp) +{ + bmp->index1 = bmp->array1_size - 1; + bmp->offset1 = RTE_BITMAP_SLAB_BIT_SIZE - 1; + __rte_bitmap_index2_set(bmp); + bmp->index2 += RTE_BITMAP_CL_SLAB_SIZE; + + bmp->go2 = 0; +} + +/** + * Bitmap memory footprint calculation + * + * @param n_bits + * Number of bits in the bitmap + * @return + * Bitmap memory footprint measured in bytes on success, 0 on error + */ +static inline uint32_t +rte_bitmap_get_memory_footprint(uint32_t n_bits) { + /* Check input arguments */ + if (n_bits == 0) { + return 0; + } + + return __rte_bitmap_get_memory_footprint(n_bits, NULL, NULL, NULL, NULL); +} + +/** + * Bitmap initialization + * + * @param mem_size + * Minimum expected size of bitmap. + * @param mem + * Base address of array1 and array2. + * @param n_bits + * Number of pre-allocated bits in array2. Must be non-zero and multiple of 512. + * @return + * Handle to bitmap instance. + */ +static inline struct rte_bitmap * +rte_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size) +{ + struct rte_bitmap *bmp; + uint32_t array1_byte_offset, array1_slabs, array2_byte_offset, array2_slabs; + uint32_t size; + + /* Check input arguments */ + if (n_bits == 0) { + return NULL; + } + + if ((mem == NULL) || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK)) { + return NULL; + } + + size = __rte_bitmap_get_memory_footprint(n_bits, + &array1_byte_offset, &array1_slabs, + &array2_byte_offset, &array2_slabs); + if (size < mem_size) { + return NULL; + } + + /* Setup bitmap */ + memset(mem, 0, size); + bmp = (struct rte_bitmap *) mem; + + bmp->array1 = (uint64_t *) &mem[array1_byte_offset]; + bmp->array1_size = array1_slabs; + bmp->array2 = (uint64_t *) &mem[array2_byte_offset]; + bmp->array2_size = array2_slabs; + + __rte_bitmap_scan_init(bmp); + + return bmp; +} + +/** + * Bitmap free + * + * @param bmp + * Handle to bitmap instance + * @return + * 0 upon success, error code otherwise + */ +static inline int +rte_bitmap_free(struct rte_bitmap *bmp) +{ + /* Check input arguments */ + if (bmp == NULL) { + return -1; + } + + return 0; +} + +/** + * Bitmap reset + * + * @param bmp + * Handle to bitmap instance + */ +static inline void +rte_bitmap_reset(struct rte_bitmap *bmp) +{ + memset(bmp->array1, 0, bmp->array1_size * sizeof(uint64_t)); + memset(bmp->array2, 0, bmp->array2_size * sizeof(uint64_t)); + __rte_bitmap_scan_init(bmp); +} + +/** + * Bitmap location prefetch into CPU L1 cache + * + * @param bmp + * Handle to bitmap instance + * @param pos + * Bit position + * @return + * 0 upon success, error code otherwise + */ +static inline void +rte_bitmap_prefetch0(struct rte_bitmap *bmp, uint32_t pos) +{ + uint64_t *slab2; + uint32_t index2; + + index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + slab2 = bmp->array2 + index2; + rte_prefetch0((void *) slab2); +} + +/** + * Bitmap bit get + * + * @param bmp + * Handle to bitmap instance + * @param pos + * Bit position + * @return + * 0 when bit is cleared, non-zero when bit is set + */ +static inline uint64_t +rte_bitmap_get(struct rte_bitmap *bmp, uint32_t pos) +{ + uint64_t *slab2; + uint32_t index2, offset2; + + index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; + slab2 = bmp->array2 + index2; + return (*slab2) & (1lu << offset2); +} + +/** + * Bitmap bit set + * + * @param bmp + * Handle to bitmap instance + * @param pos + * Bit position + */ +static inline void +rte_bitmap_set(struct rte_bitmap *bmp, uint32_t pos) +{ + uint64_t *slab1, *slab2; + uint32_t index1, index2, offset1, offset2; + + /* Set bit in array2 slab and set bit in array1 slab */ + index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; + index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); + offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; + slab2 = bmp->array2 + index2; + slab1 = bmp->array1 + index1; + + *slab2 |= 1lu << offset2; + *slab1 |= 1lu << offset1; +} + +/** + * Bitmap slab set + * + * @param bmp + * Handle to bitmap instance + * @param pos + * Bit position identifying the array2 slab + * @param slab + * Value to be assigned to the 64-bit slab in array2 + */ +static inline void +rte_bitmap_set_slab(struct rte_bitmap *bmp, uint32_t pos, uint64_t slab) +{ + uint64_t *slab1, *slab2; + uint32_t index1, index2, offset1; + + /* Set bits in array2 slab and set bit in array1 slab */ + index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); + offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; + slab2 = bmp->array2 + index2; + slab1 = bmp->array1 + index1; + + *slab2 |= slab; + *slab1 |= 1lu << offset1; +} + +static inline uint64_t +__rte_bitmap_line_not_empty(uint64_t *slab2) +{ + uint64_t v1, v2, v3, v4; + + v1 = slab2[0] | slab2[1]; + v2 = slab2[2] | slab2[3]; + v3 = slab2[4] | slab2[5]; + v4 = slab2[6] | slab2[7]; + v1 |= v2; + v3 |= v4; + + return v1 | v3; +} + +/** + * Bitmap bit clear + * + * @param bmp + * Handle to bitmap instance + * @param pos + * Bit position + */ +static inline void +rte_bitmap_clear(struct rte_bitmap *bmp, uint32_t pos) +{ + uint64_t *slab1, *slab2; + uint32_t index1, index2, offset1, offset2; + + /* Clear bit in array2 slab */ + index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; + slab2 = bmp->array2 + index2; + + /* Return if array2 slab is not all-zeros */ + *slab2 &= ~(1lu << offset2); + if (*slab2){ + return; + } + + /* Check the entire cache line of array2 for all-zeros */ + index2 &= ~ RTE_BITMAP_CL_SLAB_MASK; + slab2 = bmp->array2 + index2; + if (__rte_bitmap_line_not_empty(slab2)) { + return; + } + + /* The array2 cache line is all-zeros, so clear bit in array1 slab */ + index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); + offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; + slab1 = bmp->array1 + index1; + *slab1 &= ~(1lu << offset1); + + return; +} + +static inline int +__rte_bitmap_scan_search(struct rte_bitmap *bmp) +{ + uint64_t value1; + uint32_t i; + + /* Check current array1 slab */ + value1 = bmp->array1[bmp->index1]; + value1 &= __rte_bitmap_mask1_get(bmp); + + if (rte_bsf64(value1, &bmp->offset1)) { + return 1; + } + + __rte_bitmap_index1_inc(bmp); + bmp->offset1 = 0; + + /* Look for another array1 slab */ + for (i = 0; i < bmp->array1_size; i ++, __rte_bitmap_index1_inc(bmp)) { + value1 = bmp->array1[bmp->index1]; + + if (rte_bsf64(value1, &bmp->offset1)) { + return 1; + } + } + + return 0; +} + +static inline void +__rte_bitmap_scan_read_init(struct rte_bitmap *bmp) +{ + __rte_bitmap_index2_set(bmp); + bmp->go2 = 1; + rte_prefetch1((void *)(bmp->array2 + bmp->index2 + 8)); +} + +static inline int +__rte_bitmap_scan_read(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab) +{ + uint64_t *slab2; + + slab2 = bmp->array2 + bmp->index2; + for ( ; bmp->go2 ; bmp->index2 ++, slab2 ++, bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK) { + if (*slab2) { + *pos = bmp->index2 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2; + *slab = *slab2; + + bmp->index2 ++; + slab2 ++; + bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK; + return 1; + } + } + + return 0; +} + +/** + * Bitmap scan (with automatic wrap-around) + * + * @param bmp + * Handle to bitmap instance + * @param pos + * When function call returns 1, pos contains the position of the next set + * bit, otherwise not modified + * @param slab + * When function call returns 1, slab contains the value of the entire 64-bit + * slab where the bit indicated by pos is located. Slabs are always 64-bit + * aligned, so the position of the first bit of the slab (this bit is not + * necessarily set) is pos / 64. Once a slab has been returned by the bitmap + * scan operation, the internal pointers of the bitmap are updated to point + * after this slab, so the same slab will not be returned again if it + * contains more than one bit which is set. When function call returns 0, + * slab is not modified. + * @return + * 0 if there is no bit set in the bitmap, 1 otherwise + */ +static inline int +rte_bitmap_scan(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab) +{ + /* Return data from current array2 line if available */ + if (__rte_bitmap_scan_read(bmp, pos, slab)) { + return 1; + } + + /* Look for non-empty array2 line */ + if (__rte_bitmap_scan_search(bmp)) { + __rte_bitmap_scan_read_init(bmp); + __rte_bitmap_scan_read(bmp, pos, slab); + return 1; + } + + /* Empty bitmap */ + return 0; +} + +#ifdef __cplusplus +} +#endif + +#endif /* __INCLUDE_RTE_BITMAP_H__ */ |