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| author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2019-02-13 16:10:06 -0300 |
|---|---|---|
| committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2019-02-13 16:10:06 -0300 |
| commit | 711bab1e4d19b5c9967328315a542d93386b1ac5 (patch) | |
| tree | 65ee7e238438642e152ff52b24f042eb1491e28a /src/backend/lib | |
| parent | 754ca99314e9e1debe855b0462869ef6e58b7e7a (diff) | |
| download | postgresql-711bab1e4d19b5c9967328315a542d93386b1ac5.tar.gz | |
Add basic support for using the POPCNT and SSE4.2s LZCNT opcodes
These opcodes have been around in the AMD world since 2007, and 2008 in
the case of intel. They're supported in GCC and Clang via some __builtin
macros. The opcodes may be unavailable during runtime, in which case we
fall back on a C-based implementation of the code. In order to get the
POPCNT instruction we must pass the -mpopcnt option to the compiler. We
do this only for the pg_bitutils.c file.
David Rowley (with fragments taken from a patch by Thomas Munro)
Discussion: https://postgr.es/m/CAKJS1f9WTAGG1tPeJnD18hiQW5gAk59fQ6WK-vfdAKEHyRg2RA@mail.gmail.com
Diffstat (limited to 'src/backend/lib')
| -rw-r--r-- | src/backend/lib/bloomfilter.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/src/backend/lib/bloomfilter.c b/src/backend/lib/bloomfilter.c index 1e907cabc6..e2c1276f21 100644 --- a/src/backend/lib/bloomfilter.c +++ b/src/backend/lib/bloomfilter.c @@ -37,6 +37,7 @@ #include "access/hash.h" #include "lib/bloomfilter.h" +#include "port/pg_bitutils.h" #define MAX_HASH_FUNCS 10 @@ -187,19 +188,7 @@ double bloom_prop_bits_set(bloom_filter *filter) { int bitset_bytes = filter->m / BITS_PER_BYTE; - uint64 bits_set = 0; - int i; - - for (i = 0; i < bitset_bytes; i++) - { - unsigned char byte = filter->bitset[i]; - - while (byte) - { - bits_set++; - byte &= (byte - 1); - } - } + uint64 bits_set = pg_popcount((char *) filter->bitset, bitset_bytes); return bits_set / (double) filter->m; } |