On Thu, Oct 09, 2014 at 03:13:00PM +0800, zhangzhiqiang wrote: > On 2014/10/9 11:41, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > On Thu, Oct 09, 2014 at 11:07:04AM +0800, zhangzhiqiang wrote: > >> On 2014/10/8 21:38, Will Deacon wrote: > >>> On Wed, Oct 08, 2014 at 02:31:47PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > >>>> On Wed, Oct 08, 2014 at 10:17:41AM +0100, Will Deacon wrote: > >>>>> On Wed, Oct 08, 2014 at 04:06:12AM +0100, zhangzhiqiang wrote: > >>>>>> hi all, > >>>>>> ---------------------------------------- > >>>>>> > >>>>>> ref-cycles event is specially to Intel core, but can still used in arm architecture > >>>>>> with the wrong return value with 3.10 stable. for instance: > >>>>>> > >>>>>> perf stat -e ref-cycles sleep 1 > >>>>>> > >>>>>> Performance counter stats for 'sleep 1': > >>>>>> > >>>>>> 0 ref-cycles > >>>>>> > >>>>>> 1.002381916 seconds time elapsed > >>>>>> > >>>>>> this patch fix the bug and make it return NOT SUPPORTED > >>>>>> distinctly. > >>>>>> > >>>>>> In upstream this bug has been fixed by other way(not primary for the bug), which changes more than one file > >>>>>> and more than 1000 lines. the primary commit is 6b7658ec8a100b608e59e3cde353434db51f5be0. > >>>>>> besides we can not simply cherry-pick. > >>>>> > >>>>> I thought I saw Greg pick this up the other day? > >>>> > >>>> Yes, it's in 3.16.4, did I do something wrong by accepting it? > >>> > >>> Nah, it's a trivial patch that I struggle to get excited about. I'm just not > >>> sure why it's being sent again, after you already accepted it. > >> > >> Yes, it's in 3.16.4, in my opinion 3.10 need it too, can we put it into 3.10 or > >> do we have the plan? > > > > Does it apply to 3.10-stable? Did you test it there and see if it > > resolves your issue? > > I have tested in 3.10.56, the bug is still existing and the patch is apply to 3.10-stable. > Follow is the result without/with this patch based on 3.10.56. > > 3.10.56 without the patch: > bash-4.2# perf stat -e ref-cycles sleep 1 > > Performance counter stats for 'sleep 1': > > 0 ref-cycles > > 1.002461500 seconds time elapsed > > 3.10.56 with the patch: > bash-4.2# perf stat -e ref-cycles sleep 1 > > Performance counter stats for 'sleep 1': > > <not supported> ref-cycles > > 1.002385243 seconds time elapsed Given I have no idea what the patch even does, or is supposed to be doing, I don't know how to answer this, except it looks like I shouldn't be applying this to the 3.10-stable kernel series :) sorry, greg k-h -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html