> -----Original Message----- > From: linux-arm-kernel [mailto:[email protected]] > On Behalf Of Alexandru Elisei > Sent: Wednesday, May 20, 2020 10:31 PM> > Hi, > > On 5/18/20 12:17 PM, Alexandru Elisei wrote: > > Hi, > > > > On 5/18/20 11:45 AM, Mark Rutland wrote: > >> Hi all, > >> > >> On Mon, May 18, 2020 at 02:26:00PM +0800, Lecopzer Chen wrote: > >>> HI Sumit, > >>> > >>> Thanks for your information. > >>> > >>> I've already implemented IPI (same as you did [1], little difference > >>> in detail), hardlockup detector and perf in last year(2019) for > >>> debuggability. > >>> And now we tend to upstream to reduce kernel maintaining effort. > >>> I'm glad if someone in ARM can do this work :) > >>> > >>> Hi Julien, > >>> > >>> Does any Arm maintainers can proceed this action? > >> Alexandru (Cc'd) has been rebasing and reworking Julien's patches, > >> which is my preferred approach. > >> > >> I understand that's not quite ready for posting since he's > >> investigating some of the nastier subtleties (e.g. mutual exclusion > >> with the NMI), but maybe we can put the work-in-progress patches > >> somewhere in the mean time. > >> > >> Alexandru, do you have an idea of what needs to be done, and/or when > >> you expect you could post that? > > I'm currently working on rebasing the patches on top of 5.7-rc5, when > > I have something usable I'll post a link (should be a couple of days). > > After that I will address the review comments, and I plan to do a > > thorough testing because I'm not 100% confident that some of the > > assumptions around the locks that were removed are correct. My guess is > this will take a few weeks. > > Pushed a WIP branch on linux-arm.org [1]: > > git clone -b WIP-pmu-nmi git://linux-arm.org/linux-ae > > Practically untested, I only did perf record on a defconfig kernel running on > the > model. > > [1] > http://www.linux-arm.org/git?p=linux-ae.git;a=shortlog;h=refs/heads/WIP-pm > u-nmi
Fortunately, it does work. I used this tree to perf annotate arm_smmu_cmdq_issue_cmdlist() which is completely disabling IRQ. Luckily, it reports correct data. Before that, it reported all time was spent by the code which enabled IRQ . Barry > > Thanks, > Alex > > > > Thanks, > > Alex > >> Thanks, > >> Mark. > >> > >>> This is really useful in debugging. > >>> Thank you!! > >>> > >>> > >>> > >>> [1] https://lkml.org/lkml/2020/4/24/328 > >>> > >>> > >>> Lecopzer > >>> > >>> Sumit Garg <[email protected]> 於 2020年5月18日 週一 下午 > 1:46寫道： > >>>> + Julien > >>>> > >>>> Hi Lecopzer, > >>>> > >>>> On Sat, 16 May 2020 at 18:20, Lecopzer Chen <[email protected]> > wrote: > >>>>> These series implement Perf NMI funxtionality and depends on > >>>>> Pseudo NMI [1] which has been upstreamed. > >>>>> > >>>>> In arm64 with GICv3, Pseudo NMI was implemented for NMI-like > interruts. > >>>>> That can be extended to Perf NMI which is the prerequisite for > >>>>> hard-lockup detector which had already a standard interface inside > Linux. > >>>>> > >>>>> Thus the first step we need to implement perf NMI interface and > >>>>> make sure it works fine. > >>>>> > >>>> This is something that is already implemented via Julien's > >>>> patch-set [1]. Its v4 has been floating since July, 2019 and I > >>>> couldn't find any major blocking comments but not sure why things > >>>> haven't progressed further. > >>>> > >>>> Maybe Julien or Arm maintainers can provide updates on existing > >>>> patch-set [1] and how we should proceed further with this > >>>> interesting feature. > >>>> > >>>> And regarding hard-lockup detection, I have been able to enable it > >>>> based on perf NMI events using Julien's perf patch-set [1]. Have a > >>>> look at the patch here [2]. > >>>> > >>>> [1] https://patchwork.kernel.org/cover/11047407/ > >>>> [2] > >>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2020-May/7322 > >>>> 27.html > >>>> > >>>> -Sumit > >>>> > >>>>> Perf NMI has been test by dd if=/dev/urandom of=/dev/null like the > >>>>> link [2] did. > >>>>> > >>>>> [1] https://lkml.org/lkml/2019/1/31/535 > >>>>> [2] https://www.linaro.org/blog/debugging-arm-kernels-using-nmifiq > >>>>> > >>>>> > >>>>> Lecopzer Chen (3): > >>>>> arm_pmu: Add support for perf NMI interrupts registration > >>>>> arm64: perf: Support NMI context for perf event ISR > >>>>> arm64: Kconfig: Add support for the Perf NMI > >>>>> > >>>>> arch/arm64/Kconfig | 10 +++++++ > >>>>> arch/arm64/kernel/perf_event.c | 36 ++++++++++++++++++------ > >>>>> drivers/perf/arm_pmu.c | 51 > ++++++++++++++++++++++++++++++---- > >>>>> include/linux/perf/arm_pmu.h | 6 ++++ > >>>>> 4 files changed, 88 insertions(+), 15 deletions(-) > >>>>> > >>>>> -- > >>>>> 2.25.1
