Hm. Piddling with pgbench, which doesn't seem to collapse into a quivering heap when load exceeds cores these days, deltas weren't all that impressive, but it does appreciate the extra effort a bit, and a bit more when clients receive it as well.
If you test, and have time to piddle, you could try letting wake_wide() return 1 + sched_feat(WAKE_WIDE_IDLE) instead of adding only if wakee is the dispatcher. Numbers from my little desktop box. NO_WAKE_WIDE_IDLE postgres@homer:~> pgbench.sh clients 8 tps = 116697.697662 clients 12 tps = 115160.230523 clients 16 tps = 115569.804548 clients 20 tps = 117879.230514 clients 24 tps = 118281.753040 clients 28 tps = 116974.796627 clients 32 tps = 119082.163998 avg 117092.239 1.000 WAKE_WIDE_IDLE postgres@homer:~> pgbench.sh clients 8 tps = 124351.735754 clients 12 tps = 124419.673135 clients 16 tps = 125050.716498 clients 20 tps = 124813.042352 clients 24 tps = 126047.442307 clients 28 tps = 125373.719401 clients 32 tps = 126711.243383 avg 125252.510 1.069 1.000 WAKE_WIDE_IDLE (clients as well as server) postgres@homer:~> pgbench.sh clients 8 tps = 130539.795246 clients 12 tps = 128984.648554 clients 16 tps = 130564.386447 clients 20 tps = 129149.693118 clients 24 tps = 130211.119780 clients 28 tps = 130325.355433 clients 32 tps = 129585.656963 avg 129908.665 1.109 1.037 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
