As i know, it's only using semop, even with TAS_AND_SET defined, this is an
extract from postmaster's process registry
2515.934mS(+ 5914uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
a9 6e 10 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
2520.497mS(+ 4562uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
a9 9a 18 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
2526.496mS(+ 5998uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
a9 c6 38 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
2527.115mS(+ 619uS)[ 4] postgres(38089): semop(1568, 0x7fff1c70,
1) OK
2527.314mS(+ 198uS)[ 4] postgres(38089): semop(1568, 0x7fff1c70,
1) OK
2527.390mS(+ 76uS)[ 4] postgres(38089): semop(1568, 0x7fff1c70,
1) OK
2532.199mS(+ 4809uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
a9 f2 40 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
2537.896mS(+ 5696uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
aa 1e 48 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
2543.147mS(+ 5251uS)[ 4] postgres(38089): read(25, <00 00 00 00 68
aa 4a 68 00 00 00 22 00 a8 00 c8>..., 8192) = 8192
Thanks and regards