So I discovered recently that there is an official Jenkins plugin now. I started using it 2 weeks ago, and I have a lot of false positives on "code changes" (Already 1000 builds with 0 commit on perforce for this product).
I have ~20 different builds checking every 20 min for new changes. My view is configured like this :

//depot/product1/current/... //jenkins_ESXi_2/product1/current/...

For every false positive, this is the log scrutation jenkins gives me. It's exactly the same for every build. (and it says there are changes but of course there aren't):

Started on 9 déc. 2014 15:43:42
Polling SCM changes on master
P4: Polling with client: jenkins_ESXi_2
... found change: 77
... found change: 91
... found change: 273
... found change: 499
... found change: 511
... found change: 621
... found change: 655
... found change: 709
... found change: 733
... found change: 734
... found change: 780
... found change: 892
... found change: 903
... found change: 920
... found change: 938
... found change: 1038
... found change: 1066
... found change: 1112
... found change: 1117
... found change: 1118
... found change: 1415
... found change: 2107
... found change: 2254
... found change: 2278
... found change: 2764
... found change: 3062
... found change: 3166
... found change: 3416
... found change: 3446
... found change: 3489
... found change: 3551
... found change: 3754
... found change: 3824
... found change: 3829
... found change: 3832
... found change: 4029
... found change: 4122
... found change: 4617
... found change: 4769
... found change: 4812
... found change: 4922
... found change: 5101
... found change: 5136
... found change: 5159
... found change: 5222
... found change: 5325
... found change: 5372
Done. Took 5,1 s
Changes found