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SubjectRe: [PATCH v1 03/10] perf/x86/uncore: do not assume PCI fixed ctrs have more than 32 bits
On 02/03/2014 08:55 PM, Stephane Eranian wrote:
> The current code assumes all PCI fixed counters implement more than
> 32-bit hardware counters. The actual width is then round up to 64 to
> enable base + 8 * idx calculations.
>
> Not all PMUs necessarily implement counters with more than 32-bits.
> The patch makes the uncore_pci_perf_ctr() function dynamically
> determine the actual bits width of a pci perf counter.
>
> This patch paves the way for handling more than one uncore fixed
> counter per PMU box.
>
> Signed-off-by: Stephane Eranian <eranian@google.com>
> ---
> arch/x86/kernel/cpu/perf_event_intel_uncore.h | 31 ++++++++++++++++---------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.h b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
> index 77dc9a5..f5549cf 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.h
> +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
> @@ -548,10 +548,29 @@ unsigned uncore_pci_event_ctl(struct intel_uncore_box *box, int idx)
> return idx * 4 + box->pmu->type->event_ctl;
> }
>
> +static inline int uncore_perf_ctr_bits(struct intel_uncore_box *box)
> +{
> + return box->pmu->type->perf_ctr_bits;
> +}
> +
> +static inline int uncore_fixed_ctr_bits(struct intel_uncore_box *box)
> +{
> + return box->pmu->type->fixed_ctr_bits;
> +}
> +
> static inline
> unsigned uncore_pci_perf_ctr(struct intel_uncore_box *box, int idx)
> {
> - return idx * 8 + box->pmu->type->perf_ctr;
> + int bits, bytes;
> +
> + if (idx == UNCORE_PMC_IDX_FIXED)
> + bits = uncore_fixed_ctr_bits(box);
> + else
> + bits = uncore_perf_ctr_bits(box);
> +
> + bytes = round_up(bits, 8);

should this be "round_up(bits, 32) / 8" ?

Regards
Yan, Zheng

> +
> + return idx * bytes + box->pmu->type->perf_ctr;
> }
>
> static inline unsigned uncore_msr_box_offset(struct intel_uncore_box *box)
> @@ -633,16 +652,6 @@ unsigned uncore_perf_ctr(struct intel_uncore_box *box, int idx)
> return uncore_msr_perf_ctr(box, idx);
> }
>
> -static inline int uncore_perf_ctr_bits(struct intel_uncore_box *box)
> -{
> - return box->pmu->type->perf_ctr_bits;
> -}
> -
> -static inline int uncore_fixed_ctr_bits(struct intel_uncore_box *box)
> -{
> - return box->pmu->type->fixed_ctr_bits;
> -}
> -
> static inline int uncore_num_counters(struct intel_uncore_box *box)
> {
> return box->pmu->type->num_counters;
>



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