From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5436357C.3020300@huawei.com> Date: Thu, 9 Oct 2014 15:13:00 +0800 From: zhangzhiqiang MIME-Version: 1.0 To: "gregkh@linuxfoundation.org" CC: Will Deacon , Mark Rutland , "cov@codeaurora.org" , "lizefan@huawei.com" , "wangnan0@huawei.com" , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] arm: armv7: perf: fix armv7 ref-cycles error References: <5434AA24.7010600@huawei.com> <20141008091741.GC26140@arm.com> <20141008133147.GC5119@kroah.com> <20141008133802.GO26140@arm.com> <5435FBD8.7020109@huawei.com> <20141009034147.GC19906@kroah.com> In-Reply-To: <20141009034147.GC19906@kroah.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 2014/10/9 11:41, gregkh@linuxfoundation.org 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@linuxfoundation.org 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': ref-cycles 1.002385243 seconds time elapsed Best wishes, zhangzhiqiang