DPDK 21.11.9
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#include <string.h>
#include <rte_common.h>
#include <rte_config.h>
#include <rte_debug.h>
#include <rte_memory.h>
#include <rte_branch_prediction.h>
#include <rte_prefetch.h>
Go to the source code of this file.
Data Structures | |
struct | rte_bitmap |
Functions | |
static uint32_t | rte_bitmap_get_memory_footprint (uint32_t n_bits) |
static struct rte_bitmap * | rte_bitmap_init (uint32_t n_bits, uint8_t *mem, uint32_t mem_size) |
static __rte_experimental void | __rte_bitmap_clear_slab_overhead_bits (uint64_t *slabs, uint32_t slab_size, uint32_t pos) |
static __rte_experimental struct rte_bitmap * | rte_bitmap_init_with_all_set (uint32_t n_bits, uint8_t *mem, uint32_t mem_size) |
static int | rte_bitmap_free (struct rte_bitmap *bmp) |
static void | rte_bitmap_reset (struct rte_bitmap *bmp) |
static void | rte_bitmap_prefetch0 (struct rte_bitmap *bmp, uint32_t pos) |
static uint64_t | rte_bitmap_get (struct rte_bitmap *bmp, uint32_t pos) |
static void | rte_bitmap_set (struct rte_bitmap *bmp, uint32_t pos) |
static void | rte_bitmap_set_slab (struct rte_bitmap *bmp, uint32_t pos, uint64_t slab) |
static void | rte_bitmap_clear (struct rte_bitmap *bmp, uint32_t pos) |
static int | rte_bitmap_scan (struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab) |
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.
Definition in file rte_bitmap.h.
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inlinestatic |
Bitmap memory footprint calculation
n_bits | Number of bits in the bitmap |
Definition at line 148 of file rte_bitmap.h.
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inlinestatic |
Bitmap initialization
n_bits | Number of pre-allocated bits in array2. |
mem | Base address of array1 and array2. |
mem_size | Minimum expected size of bitmap. |
Definition at line 170 of file rte_bitmap.h.
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inlinestatic |
Bitmap clear slab overhead bits.
slabs | Slab array. |
slab_size | Number of 64-bit slabs in the slabs array. |
pos | The start bit position in the slabs to be cleared. |
Definition at line 220 of file rte_bitmap.h.
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inlinestatic |
Bitmap initialization with all bits set
n_bits | Number of pre-allocated bits in array2. |
mem | Base address of array1 and array2. |
mem_size | Minimum expected size of bitmap. |
Definition at line 254 of file rte_bitmap.h.
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inlinestatic |
Bitmap free
bmp | Handle to bitmap instance |
Definition at line 299 of file rte_bitmap.h.
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inlinestatic |
Bitmap reset
bmp | Handle to bitmap instance |
Definition at line 316 of file rte_bitmap.h.
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inlinestatic |
Bitmap location prefetch into CPU L1 cache
bmp | Handle to bitmap instance |
pos | Bit position |
Definition at line 332 of file rte_bitmap.h.
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inlinestatic |
Bitmap bit get
bmp | Handle to bitmap instance |
pos | Bit position |
Definition at line 353 of file rte_bitmap.h.
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inlinestatic |
Bitmap bit set
bmp | Handle to bitmap instance |
pos | Bit position |
Definition at line 373 of file rte_bitmap.h.
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inlinestatic |
Bitmap slab set
bmp | Handle to bitmap instance |
pos | Bit position identifying the array2 slab |
slab | Value to be assigned to the 64-bit slab in array2 |
Definition at line 401 of file rte_bitmap.h.
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inlinestatic |
Bitmap bit clear
bmp | Handle to bitmap instance |
pos | Bit position |
Definition at line 466 of file rte_bitmap.h.
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inlinestatic |
Bitmap scan (with automatic wrap-around)
bmp | Handle to bitmap instance |
pos | When function call returns 1, pos contains the position of the next set bit, otherwise not modified |
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. |
Definition at line 575 of file rte_bitmap.h.