DPDK中的BitMap测试

1、简介

看了内核的bitmap实现，比较复杂。之后看了dpdk的bitmap，可移植出来成为模块。

2、BitMap源码

代码源自：dpdk-25.07\lib\eal\include\rte_bitmap.h

#ifndef _BITMAP_H
#define _BITMAP_H#include <string.h>
#include <stdlib.h>
#include <stdint.h>#define RTE_CACHE_LINE_SIZE 	     64/** Cache line size in terms of log2 */
#if RTE_CACHE_LINE_SIZE == 64#define RTE_CACHE_LINE_SIZE_LOG2 6
#elif RTE_CACHE_LINE_SIZE == 128#define RTE_CACHE_LINE_SIZE_LOG2 7
#else#error "Unsupported cache line size"
#endif/** Cache line mask. */
#define RTE_CACHE_LINE_MASK (RTE_CACHE_LINE_SIZE-1)/* 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[];
};static inline uint32_t
rte_combine32ms1b(uint32_t x)
{x |= x >> 1;x |= x >> 2;x |= x >> 4;x |= x >> 8;x |= x >> 16;return x;
}static inline uint32_t
rte_align32pow2(uint32_t x)
{x--;x = rte_combine32ms1b(x);return x + 1;
}/******************************************/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 (~1llu) << 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);
}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 n_bits*   Number of pre-allocated bits in array2.* @param mem*   Base address of array1 and array2.* @param mem_size*   Minimum expected size of bitmap.* @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 clear slab overhead bits.** @param slabs*   Slab array.* @param slab_size*   Number of 64-bit slabs in the slabs array.* @param pos*   The start bit position in the slabs to be cleared.*/
static inline void
__rte_bitmap_clear_slab_overhead_bits(uint64_t *slabs, uint32_t slab_size,uint32_t pos)
{uint32_t i;uint32_t index = pos / RTE_BITMAP_SLAB_BIT_SIZE;uint32_t offset = pos & RTE_BITMAP_SLAB_BIT_MASK;if (offset) {for (i = offset; i < RTE_BITMAP_SLAB_BIT_SIZE; i++)slabs[index] &= ~(1llu << i);index++;}if (index < slab_size)memset(&slabs[index], 0, sizeof(slabs[0]) *(slab_size - index));
}/*** Bitmap initialization with all bits set** @param n_bits*   Number of pre-allocated bits in array2.* @param mem*   Base address of array1 and array2.* @param mem_size*   Minimum expected size of bitmap.* @return*   Handle to bitmap instance.*/
static inline struct rte_bitmap *
rte_bitmap_init_with_all_set(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
{struct rte_bitmap *bmp;uint32_t array1_byte_offset, array1_slabs;uint32_t array2_byte_offset, array2_slabs;uint32_t size;/* Check input arguments */if (!n_bits || !mem || (((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 */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);memset(bmp->array1, 0xff, bmp->array1_size * sizeof(bmp->array1[0]));memset(bmp->array2, 0xff, bmp->array2_size * sizeof(bmp->array2[0]));/* Clear overhead bits. */__rte_bitmap_clear_slab_overhead_bits(bmp->array1, bmp->array1_size,bmp->array2_size >> RTE_BITMAP_CL_SLAB_SIZE_LOG2);__rte_bitmap_clear_slab_overhead_bits(bmp->array2, bmp->array2_size,n_bits);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*/
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) & (1llu << 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 |= 1llu << offset2;*slab1 |= 1llu << 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 |= 1llu << offset1;
}#if RTE_BITMAP_CL_SLAB_SIZE == 8
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;
}#elif RTE_BITMAP_CL_SLAB_SIZE == 16
static inline uint64_t
__rte_bitmap_line_not_empty(uint64_t *slab2)
{uint64_t v1, v2, v3, v4, v5, v6, v7, v8;v1 = slab2[0] | slab2[1];v2 = slab2[2] | slab2[3];v3 = slab2[4] | slab2[5];v4 = slab2[6] | slab2[7];v5 = slab2[8] | slab2[9];v6 = slab2[10] | slab2[11];v7 = slab2[12] | slab2[13];v8 = slab2[14] | slab2[15];v1 |= v2;v3 |= v4;v5 |= v6;v7 |= v8;return v1 | v3 | v5 | v7;
}#endif /* RTE_BITMAP_CL_SLAB_SIZE *//*** 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 &= ~(1llu << 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 &= ~(1llu << 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_safe(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_safe(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;
}#endif /* _BITMAP_H */

测试代码 test_bitmap.c：

#include "bitmap.h"#define MAX_BITS 31void *
rte_zmalloc(const char *type, size_t size, unsigned align)
{return calloc(size / RTE_CACHE_LINE_SIZE, RTE_CACHE_LINE_SIZE);
}int main(void)
{void *mem;uint32_t bmp_size;struct rte_bitmap *bmp;printf("uint64_t len:%u\n", sizeof(uint64_t));bmp_size = rte_bitmap_get_memory_footprint(MAX_BITS);printf("bmp_size:%u\n", bmp_size);mem = rte_zmalloc("bitmap", bmp_size, RTE_CACHE_LINE_SIZE);if (mem == NULL){printf("Failed to allocate memory for bitmap\n");return -1;}// bitmap initbmp = rte_bitmap_init(MAX_BITS, mem, bmp_size);if (bmp == NULL){printf("Failed to init bitmap\n");return -1;}rte_bitmap_set(bmp, 2);printf("Bit2: 0x%lx\n", rte_bitmap_get(bmp, 2));rte_bitmap_clear(bmp, 2);printf("Bit2: 0x%lx\n", rte_bitmap_get(bmp, 2));rte_bitmap_set(bmp, 0);rte_bitmap_set(bmp, 1);printf("Bit0: 0x%lx\n", rte_bitmap_get(bmp, 0));printf("Bit1: 0x%lx\n", rte_bitmap_get(bmp, 1));rte_bitmap_reset(bmp);printf("Bit0: 0x%lx\n", rte_bitmap_get(bmp, 0));printf("Bit1: 0x%lx\n", rte_bitmap_get(bmp, 1));rte_bitmap_free(bmp);free(mem);return 0;
}

测试结果：

sunny@ubuntu:~/test/bitmap/build$ ./test_bitmap 
uint64_t len:8
bmp_size:128
Bit2: 0x4
Bit2: 0x0
Bit0: 0x1
Bit1: 0x2
Bit0: 0x0
Bit1: 0x0