On 13.01.17 14:15:00, Robert Richter wrote: > On 13.01.17 09:19:04, Will Deacon wrote: > > On Thu, Jan 12, 2017 at 07:58:25PM +0100, Robert Richter wrote: > > > On 12.01.17 16:05:36, Will Deacon wrote: > > > > On Mon, Jan 09, 2017 at 12:53:20PM +0100, Robert Richter wrote: > > > > > > > > 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? > > > > > > I built it in a loop on the shell, so no reboots between builds. Note > > > that I was building the kernel in /dev/shm to not access harddisks. I > > > think build times should be comparable then since there is no fs > > > caching. > > > > I guess I'm really asking what the standard deviation is if you *do* reboot > > between builds, using the same kernel. It's hard to tell whether the numbers > > are due to the patches, or just because of noise incurred by the way things > > happen to initialise. > > Ok, I am going to test this. See below the data for a test with reboots between every 3 builds (9 builds per kernel). Though some deviation can be seen between reboots there is a trend. -Robert pfn_valid_within(), boot #1: real 6m0.007s user 372m55.709s sys 16m45.962s real 5m58.718s user 372m58.852s sys 16m47.675s real 5m58.481s user 372m56.172s sys 16m46.953s pfn_valid_within(), Boot #2: real 6m1.163s user 372m57.282s sys 16m52.025s real 6m0.562s user 373m4.957s sys 16m52.847s real 6m0.030s user 372m54.710s sys 16m54.516s pfn_valid_within(), Boot #3: real 6m1.784s user 373m13.379s sys 16m48.388s real 5m58.579s user 373m10.403s sys 16m47.628s real 5m59.151s user 373m0.084s sys 16m50.634s early_pfn_valid(), Boot #1: real 5m59.902s user 372m57.201s sys 16m42.157s real 5m59.510s user 372m59.762s sys 16m47.331s real 5m58.559s user 372m46.530s sys 16m49.010s early_pfn_valid(), Boot #2: real 6m0.652s user 373m10.785s sys 16m25.138s real 5m58.663s user 373m4.498s sys 16m28.262s real 5m57.675s user 373m6.174s sys 16m28.653s early_pfn_valid(), Boot #3: real 5m59.680s user 373m4.007s sys 16m26.781s real 5m58.234s user 372m58.895s sys 16m26.957s real 5m58.707s user 372m40.546s sys 16m29.345s -- 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>