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wangyuan pushed a commit to branch unstable
in repository https://gitbox.apache.org/repos/asf/incubator-kvrocks.git
The following commit(s) were added to refs/heads/unstable by this push:
new b433419 Optimize get bitmap string and remove redundant num2bit array
(#793)
b433419 is described below
commit b4334195b981f64e24fdb6b3224d07f77b567ccd
Author: ColinChamber <[email protected]>
AuthorDate: Wed Aug 31 11:37:19 2022 +0800
Optimize get bitmap string and remove redundant num2bit array (#793)
---
src/redis_bitmap.cc | 40 +++++++++++++++++++++++++++++-----------
src/redis_bitmap_string.cc | 14 ++++----------
2 files changed, 33 insertions(+), 21 deletions(-)
diff --git a/src/redis_bitmap.cc b/src/redis_bitmap.cc
index eb0907c..4fbcfe4 100644
--- a/src/redis_bitmap.cc
+++ b/src/redis_bitmap.cc
@@ -35,7 +35,7 @@ const uint32_t kBitmapSegmentBytes = 1024;
const char kErrBitmapStringOutOfRange[] = "The size of the bitmap string
exceeds the "
"configuration item
max-bitmap-to-string-mb";
-uint32_t kNum2Bits[256] = {
+extern const uint8_t kNum2Bits[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
@@ -144,18 +144,36 @@ rocksdb::Status Bitmap::GetString(const Slice &user_key,
const uint32_t max_btos
static_cast<size_t>(kBitmapSegmentBytes),
static_cast<size_t>(metadata.size - frag_index)});
- // If you setbit bit 0 1, the value is stored as 0x01 in Kvrocks but 0x80
in Redis.
- // So we need to swap bits is to keep the same return value as Redis.
+ /*
+ * If you setbit bit 0 1, the value is stored as 0x01 in Kvrocks but 0x80
in Redis.
+ * So we need to swap bits is to keep the same return value as Redis.
+ * This swap table is generated according to the following mapping
definition.
+ * swap_table(x) = ((x & 0x80) >> 7)| ((x & 0x40) >> 5)|\
+ * ((x & 0x20) >> 3)| ((x & 0x10) >> 1)|\
+ * ((x & 0x08) << 1)| ((x & 0x04) << 3)|\
+ * ((x & 0x02) << 5)| ((x & 0x01) << 7);
+ */
+ static const uint8_t swap_table[256] = {
+ 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50,
0xD0, 0x30, 0xB0, 0x70, 0xF0,
+ 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58,
0xD8, 0x38, 0xB8, 0x78, 0xF8,
+ 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54,
0xD4, 0x34, 0xB4, 0x74, 0xF4,
+ 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C,
0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+ 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52,
0xD2, 0x32, 0xB2, 0x72, 0xF2,
+ 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A,
0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+ 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56,
0xD6, 0x36, 0xB6, 0x76, 0xF6,
+ 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E, 0x5E,
0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+ 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51,
0xD1, 0x31, 0xB1, 0x71, 0xF1,
+ 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59,
0xD9, 0x39, 0xB9, 0x79, 0xF9,
+ 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, 0x15, 0x95, 0x55,
0xD5, 0x35, 0xB5, 0x75, 0xF5,
+ 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D,
0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+ 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53,
0xD3, 0x33, 0xB3, 0x73, 0xF3,
+ 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B,
0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+ 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57,
0xD7, 0x37, 0xB7, 0x77, 0xF7,
+ 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F,
0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+ };
for (uint32_t i = 0; i < valid_size; i++) {
if (!fragment[i]) continue;
- fragment[i] = ((fragment[i] & 0x80) >> 7)|\
- ((fragment[i] & 0x40) >> 5)|\
- ((fragment[i] & 0x20) >> 3)|\
- ((fragment[i] & 0x10) >> 1)|\
- ((fragment[i] & 0x08) << 1)|\
- ((fragment[i] & 0x04) << 3)|\
- ((fragment[i] & 0x02) << 5)|\
- ((fragment[i] & 0x01) << 7);
+ fragment[i] = swap_table[static_cast<uint8_t>(fragment[i])];;
}
value->replace(frag_index, valid_size, fragment.data(), valid_size);
}
diff --git a/src/redis_bitmap_string.cc b/src/redis_bitmap_string.cc
index 74b8e0b..8badca1 100644
--- a/src/redis_bitmap_string.cc
+++ b/src/redis_bitmap_string.cc
@@ -26,6 +26,8 @@
namespace Redis {
+extern const uint8_t kNum2Bits[256];
+
rocksdb::Status BitmapString::GetBit(const std::string &raw_value, uint32_t
offset, bool *bit) {
auto string_value = raw_value.substr(STRING_HDR_SIZE, raw_value.size() -
STRING_HDR_SIZE);
uint32_t byte_index = offset >> 3;
@@ -136,18 +138,10 @@ rocksdb::Status BitmapString::BitPos(const std::string
&raw_value,
size_t BitmapString::redisPopcount(unsigned char *p, int64_t count) {
size_t bits = 0;
uint32_t *p4;
- static const unsigned char bitsinbyte[256] =
- {0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4,
2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3,
- 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5,
5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,
- 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,
3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4,
- 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3,
3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5,
- 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6,
- 6, 7, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5,
5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5,
- 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7,
6, 7, 7, 8};
/* Count initial bytes not aligned to 32 bit. */
while (reinterpret_cast<uint64_t>(p) & 3 && count) {
- bits += bitsinbyte[*p++];
+ bits += kNum2Bits[*p++];
count--;
}
@@ -189,7 +183,7 @@ size_t BitmapString::redisPopcount(unsigned char *p,
int64_t count) {
}
/* Count the remaining bytes. */
p = (unsigned char *) p4;
- while (count--) bits += bitsinbyte[*p++];
+ while (count--) bits += kNum2Bits[*p++];
return bits;
}
