Re: [PATCH 2/3] perf/x86/pebs: add workaround for broken OVFL status on HSW

[Stephane Eranian]

On Tue, Mar 8, 2016 at 9:34 PM, Stephane Eranian <eranian@xxxxxxxxxx> wrote:
> On Tue, Mar 8, 2016 at 1:13 PM, Stephane Eranian <eranian@xxxxxxxxxx> wrote:
>> Hi,
>>
>> On Tue, Mar 8, 2016 at 1:07 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>> On Tue, Mar 08, 2016 at 12:59:23PM -0800, Stephane Eranian wrote:
>>>> hi,
>>>>
>>>> On Mon, Mar 7, 2016 at 12:25 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>>> >
>>>> > On Mon, Mar 07, 2016 at 07:27:31PM +0100, Jiri Olsa wrote:
>>>> > > On Mon, Mar 07, 2016 at 01:18:40PM +0100, Peter Zijlstra wrote:
>>>> > > > On Mon, Mar 07, 2016 at 11:24:13AM +0100, Peter Zijlstra wrote:
>>>> > > >
>>>> > > > > I suspect Andi is having something along:
>>>> > > > >
>>>> > > > >  lkml.kernel.org/r/1445458568-16956-1-git-send-email-andi@xxxxxxxxxxxxxx
>>>> > > > >
>>>> > > > > applied to his tree.
>>>> > > >
>>>> > > > OK, I munged a bunch of patches together, please have a hard look at the
>>>> > > > end result found in:
>>>> > > >
>>>> > > >   git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git perf/core
>>>> > > >
>>>>
>>>> I ran this kernel on Haswell. Even with Andi's fixes the problem I identified is
>>>> still there, so my patch is still needed.
>>>
>>> Right, your patch should be included in that kernel, or did I make a
>>> royal mess of things?
>>>
>> No, it is as expected for the OVF PMI fix.
>>
>>> I put Andi's late status ack on top of your patch.
>>>
> Ok, I ran into a problem on Broadwell with your branch with Andi's
> patches. I see

Sorry this is with tip.git and not your branch. Will try with it too.

> a problem which had disappeared since SandyBridge:
>
> 11551.128422] ------------[ cut here ]------------
> [11551.128435] WARNING: CPU: 3 PID: 12114 at
> arch/x86/events/intel/core.c:1868 intel_pmu_handle_irq+0x2da/0x4b0()
> [11551.128437] perfevents: irq loop stuck!
> [11551.128469]  <NMI>  [<ffffffff81663975>] dump_stack+0x4d/0x63
> [11551.128479]  [<ffffffff810b8657>] warn_slowpath_common+0x97/0xe0
> [11551.128482]  [<ffffffff810b8756>] warn_slowpath_fmt+0x46/0x50
> [11551.128486]  [<ffffffff8100b6ca>] intel_pmu_handle_irq+0x2da/0x4b0
> [11551.128491]  [<ffffffff81004569>] perf_event_nmi_handler+0x39/0x60
> [11551.128494]  [<ffffffff8107be61>] nmi_handle+0x61/0x110
> [11551.128497]  [<ffffffff8107c684>] default_do_nmi+0x44/0x110
> [11551.128500]  [<ffffffff8107c827>] do_nmi+0xd7/0x140
> [11551.128504]  [<ffffffff8166e127>] end_repeat_nmi+0x1a/0x1e
> [11551.128507]  [<ffffffff81009dd6>] ? native_write_msr+0x6/0x30
> [11551.128510]  [<ffffffff81009dd6>] ? native_write_msr+0x6/0x30
> [11551.128514]  [<ffffffff81009dd6>] ? native_write_msr+0x6/0x30
> [11551.128515]  <<EOE>>  [<ffffffff8100b385>] ?
> intel_pmu_enable_event+0x215/0x230
> [11551.128520]  [<ffffffff81005a0d>] x86_pmu_start+0x8d/0x120
> [11551.128523]  [<ffffffff810061db>] x86_pmu_enable+0x27b/0x2f0
> [11551.128527]  [<ffffffff8118d63d>] perf_pmu_enable+0x1d/0x30
> [11551.128530]  [<ffffffff81191bca>] ctx_resched+0x5a/0x70
> [11551.128532]  [<ffffffff81191d8c>] __perf_event_enable+0x1ac/0x210
> [11551.128537]  [<ffffffff81188f81>] event_function+0xa1/0x170
> [11551.128540]  [<ffffffff811899b0>] ? perf_duration_warn+0x70/0x70
> [11551.128543]  [<ffffffff811899f7>] remote_function+0x47/0x60
> [11551.128547]  [<ffffffff8112a178>] generic_exec_single+0xa8/0xb0
> [11551.128550]  [<ffffffff811899b0>] ? perf_duration_warn+0x70/0x70
> [11551.128553]  [<ffffffff811899b0>] ? perf_duration_warn+0x70/0x70
> [11551.128555]  [<ffffffff8112a298>] smp_call_function_single+0xa8/0x100
> [11551.128559]  [<ffffffff8118aec4>] event_function_call+0x84/0x100
> [11551.128561]  [<ffffffff81191be0>] ? ctx_resched+0x70/0x70
> [11551.128564]  [<ffffffff81191be0>] ? ctx_resched+0x70/0x70
> [11551.128566]  [<ffffffff81188ee0>] ? perf_ctx_lock+0x30/0x30
> [11551.128570]  [<ffffffff8118b050>] _perf_event_enable+0x60/0x80
> [11551.128572]  [<ffffffff8118fc61>] perf_ioctl+0x271/0x3e0
>
> The infinite loop in the irq handler!
>
> But here it seems there is a race with a perf_events ioctl() to likely
> reset the period.
> I am not using the perf tool here just running a self-monitoring task.
>
>
>>> Also note, Ingo merged most of those patches today, all except the top
>>> 3, because Andi wanted to double check something.
>>