Nevermind, I got it to work, sorry for the noise...
greg k-h
On Mon, Dec 12, 2016 at 02:37:22PM -0800, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> >From 7f612a7f0bc13a2361a152862435b7941156b6af Mon Sep 17 00:00:00 2001
> From: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
> Date: Tue, 29 Nov 2016 20:33:28 +0000
> Subject: [PATCH] perf/x86: Fix full width counter, counter overflow
>
> Lukasz reported that perf stat counters overflow handling is broken on KNL/SLM.
>
> Both these parts have full_width_write set, and that does indeed have
> a problem. In order to deal with counter wrap, we must sample the
> counter at at least half the counter period (see also the sampling
> theorem) such that we can unambiguously reconstruct the count.
>
> However commit:
>
> 069e0c3c4058 ("perf/x86/intel: Support full width counting")
>
> sets the sampling interval to the full period, not half.
>
> Fixing that exposes another issue, in that we must not sign extend the
> delta value when we shift it right; the counter cannot have
> decremented after all.
>
> With both these issues fixed, counter overflow functions correctly
> again.
>
> Reported-by: Lukasz Odzioba <lukasz.odzioba@xxxxxxxxx>
> Tested-by: Liang, Kan <kan.liang@xxxxxxxxx>
> Tested-by: Odzioba, Lukasz <lukasz.odzioba@xxxxxxxxx>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Stephane Eranian <eranian@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 069e0c3c4058 ("perf/x86/intel: Support full width counting")
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
>
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index 9d4bf3ab049e..6e395c996900 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -69,7 +69,7 @@ u64 x86_perf_event_update(struct perf_event *event)
> int shift = 64 - x86_pmu.cntval_bits;
> u64 prev_raw_count, new_raw_count;
> int idx = hwc->idx;
> - s64 delta;
> + u64 delta;
>
> if (idx == INTEL_PMC_IDX_FIXED_BTS)
> return 0;
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index a74a2dbc0180..cb8522290e6a 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -4034,7 +4034,7 @@ __init int intel_pmu_init(void)
>
> /* Support full width counters using alternative MSR range */
> if (x86_pmu.intel_cap.full_width_write) {
> - x86_pmu.max_period = x86_pmu.cntval_mask;
> + x86_pmu.max_period = x86_pmu.cntval_mask >> 1;
> x86_pmu.perfctr = MSR_IA32_PMC0;
> pr_cont("full-width counters, ");
> }
>
> --
> 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
--
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