参考文献: http://www.dragonflybsd.org/docs/newhandbook/Upgrading/
# cd /usr
# time make src-create
53.213u 16.540s 11:35.97 10.0% 803+161k 272+440io 42pf+0w
# cd /usr/src
# git tag
# git branch -r
# git checkout -b DragonFly_RELEASE_3_2 origin/DragonFly_RELEASE_3_2
# time make buildworld
4572.140u 2539.571s 2:00:20.95 98.4% 3580+628k 149988+0io 5484pf+0w
# time make buildkernel
649.975u 309.232s 16:19.33 97.9% 3514+622k 41474+0io 524pf+0w
# time make installkernel
4.981u 13.866s 0:29.06 64.8% 289+163k 7930+10604io 44pf+0w
# time make installworld
16.187u 74.581s 1:51.38 81.4% 271+166k 38112+180io 226pf+0w
# time make upgrade
0.960u 1.812s 0:03.27 84.7% 112+96k 3758+0io 80pf+0w
失敗したので別のビルド試す
# git checkout -b DragonFly_RELEASE_3_0 origin/DragonFly_RELEASE_3_0
# time make buildworld
4086.548u 2244.935s 1:47:00.38 98.6% 3443+613k 118970+0io 3344pf+0w
# time make buildkernel
622.694u 297.667s 15:40.58 97.8% 3494+619k 38820+0io 520pf+0w
# time make installkernel
4.357u 12.549s 0:21.54 78.4% 281+163k 7234+11942io 50pf+0w
# time make installworld
14.892u 63.452s 1:38.80 79.2% 277+169k 29092+184io 196pf+0w
# time make upgrade
0.382u 0.734s 0:01.15 96.5% 164+113k 0+0io 4pf+0w