Hi Robert, On Mon, Jan 09, 2017 at 12:53:20PM +0100, Robert Richter wrote: > On 06.01.17 08:37:25, Ard Biesheuvel wrote: > > Any comments on the performance impact (including boot time) ? > > I did a kernel compile test and kernel mode time increases by about > 2.2%. Though this is already significant, we need a more suitable mem > benchmark here for further testing. Thanks for doing this. > For boot time I dont see significant changes. > > -Robert > > > Boot times: > > pfn_valid_within(): > [ 25.929134] > [ 25.548830] > [ 25.503225] > > early_pfn_valid() v3: > [ 25.773814] > [ 25.548428] > [ 25.765290] > > > Kernel compile times (3 runs each): > > pfn_valid_within(): > > real 6m4.088s > user 372m57.607s > sys 16m55.158s > > real 6m1.532s > user 372m48.453s > sys 16m50.370s > > real 6m4.061s > user 373m18.753s > sys 16m57.027s Did you reboot the machine between each build here, or only when changing kernel? If the latter, do you see variations in kernel build time by simply rebooting the same Image? Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>