> I gave the patch below a try and we are reaching the same results,
> even better. The simplest solution is always the best. Nick, you
> should send that single patch.
FYI, here are results in a KVM guests with pinned vCPUs.
* P9 DD2.2 - 2s * 64 threads - KVM guest :
IPI/sys IPI/chip
----------- --------------------------------
--------------------------------
unhandled unhandled
chips cpus noirqdebug detection noirqdebug detection
----------- --------------------------------
--------------------------------
1 0-15 4.152813 4.084240 4.061028 4.097700 4.042539
4.008314
0-31 8.186328 8.157970 7.937127 8.277942 8.019539
7.831189
0-47 11.391635 11.232960 11.017530 11.278048 10.994501
10.889347
0-63 13.907476 14.022307 11.460280 13.933946 13.506828
11.369188
2 0-79 18.105276 18.084463 8.376047 18.069176 17.587916
15.477006
0-95 22.100683 22.265763 7.338229 22.084006 21.588463
19.502192
0-111 25.305948 25.473068 6.716235 25.429261 24.607570
22.733253
0-127 27.814449 28.029029 6.222736 27.960119 27.253432
23.884916
The three columns "IPI/chip" are results with this series. "IPI/sys" are
without. The "unhandled detection" columns are with Nick's patch.
C.
