Re: [dpdk-dev] [PATCH v2 4/4] event/octeontx2: timer always use virtual counter

[Jerin Jacob <jerinjacobk@gmail.com>]

On Sun, Mar 21, 2021 at 2:20 PM <pbhagavatula@marvell.com> wrote:
>
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Use virtual counter for estimating current bucket as PMU cannot be
> reliably used to estimate time.
>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>


There is a genuine Travis build issue with this patch. Please check

http://patches.dpdk.org/project/dpdk/patch/20210321084915.2649-4-pbhagavatula@marvell.com/
https://travis-ci.com/github/ovsrobot/dpdk/builds/220728709

> ---
>  drivers/event/octeontx2/otx2_tim_evdev.c  | 19 +++--------------
>  drivers/event/octeontx2/otx2_tim_evdev.h  | 26 +++++++++++++++++++++++
>  drivers/event/octeontx2/otx2_tim_worker.c |  4 ++--
>  drivers/event/octeontx2/otx2_tim_worker.h |  2 +-
>  4 files changed, 32 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/event/octeontx2/otx2_tim_evdev.c b/drivers/event/octeontx2/otx2_tim_evdev.c
> index 4fb002ddb..926c2dce6 100644
> --- a/drivers/event/octeontx2/otx2_tim_evdev.c
> +++ b/drivers/event/octeontx2/otx2_tim_evdev.c
> @@ -354,7 +354,7 @@ otx2_tim_calibrate_start_tsc(struct otx2_tim_ring *tim_ring)
>
>         for (icount = 0; icount < OTX2_TIM_CALIB_ITER; icount++) {
>                 real_bkt = otx2_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
> -               bkt_cyc = rte_rdtsc();
> +               bkt_cyc = tim_cntvct();
>                 bucket = (bkt_cyc - tim_ring->ring_start_cyc) /
>                                                         tim_ring->tck_int;
>                 bucket = bucket % (tim_ring->nb_bkts);
> @@ -389,20 +389,8 @@ otx2_tim_ring_start(const struct rte_event_timer_adapter *adptr)
>                 tim_err_desc(rc);
>                 goto fail;
>         }
> -#ifdef RTE_ARM_EAL_RDTSC_USE_PMU
> -       uint64_t tenns_stmp, tenns_diff;
> -       uint64_t pmu_stmp;
> -
> -       pmu_stmp = rte_rdtsc();
> -       asm volatile("mrs %0, cntvct_el0" : "=r" (tenns_stmp));
> -
> -       tenns_diff = tenns_stmp - rsp->timestarted;
> -       pmu_stmp = pmu_stmp - (NSEC2TICK(tenns_diff  * 10, rte_get_timer_hz()));
> -       tim_ring->ring_start_cyc = pmu_stmp;
> -#else
>         tim_ring->ring_start_cyc = rsp->timestarted;
> -#endif
> -       tim_ring->tck_int = NSEC2TICK(tim_ring->tck_nsec, rte_get_timer_hz());
> +       tim_ring->tck_int = NSEC2TICK(tim_ring->tck_nsec, tim_cntfrq());
>         tim_ring->tot_int = tim_ring->tck_int * tim_ring->nb_bkts;
>         tim_ring->fast_div = rte_reciprocal_value_u64(tim_ring->tck_int);
>         tim_ring->fast_bkt = rte_reciprocal_value_u64(tim_ring->nb_bkts);
> @@ -470,8 +458,7 @@ otx2_tim_stats_get(const struct rte_event_timer_adapter *adapter,
>                    struct rte_event_timer_adapter_stats *stats)
>  {
>         struct otx2_tim_ring *tim_ring = adapter->data->adapter_priv;
> -       uint64_t bkt_cyc = rte_rdtsc() - tim_ring->ring_start_cyc;
> -
> +       uint64_t bkt_cyc = tim_cntvct() - tim_ring->ring_start_cyc;
>
>         stats->evtim_exp_count = __atomic_load_n(&tim_ring->arm_cnt,
>                                                  __ATOMIC_RELAXED);
> diff --git a/drivers/event/octeontx2/otx2_tim_evdev.h b/drivers/event/octeontx2/otx2_tim_evdev.h
> index 0667d4576..410880e14 100644
> --- a/drivers/event/octeontx2/otx2_tim_evdev.h
> +++ b/drivers/event/octeontx2/otx2_tim_evdev.h
> @@ -176,6 +176,32 @@ tim_priv_get(void)
>         return mz->addr;
>  }
>
> +#ifdef RTE_ARCH_ARM64
> +static inline uint64_t
> +tim_cntvct(void)
> +{
> +       return __rte_arm64_cntvct();
> +}
> +
> +static inline uint64_t
> +tim_cntfrq(void)
> +{
> +       return __rte_arm64_cntfrq();
> +}
> +#else
> +static inline uint64_t
> +tim_cntvct(void)
> +{
> +       return 0;
> +}
> +
> +static inline uint64_t
> +tim_cntfrq(void)
> +{
> +       return 0;
> +}
> +#endif
> +
>  #define TIM_ARM_FASTPATH_MODES                                                 \
>         FP(sp, 0, 0, 0, OTX2_TIM_ENA_DFB | OTX2_TIM_SP)                        \
>         FP(mp, 0, 0, 1, OTX2_TIM_ENA_DFB | OTX2_TIM_MP)                        \
> diff --git a/drivers/event/octeontx2/otx2_tim_worker.c b/drivers/event/octeontx2/otx2_tim_worker.c
> index 6a3511ec0..9ee07958f 100644
> --- a/drivers/event/octeontx2/otx2_tim_worker.c
> +++ b/drivers/event/octeontx2/otx2_tim_worker.c
> @@ -41,12 +41,12 @@ tim_format_event(const struct rte_event_timer * const tim,
>  static inline void
>  tim_sync_start_cyc(struct otx2_tim_ring *tim_ring)
>  {
> -       uint64_t cur_cyc = rte_rdtsc();
> +       uint64_t cur_cyc = tim_cntvct();
>         uint32_t real_bkt;
>
>         if (cur_cyc - tim_ring->last_updt_cyc > tim_ring->tot_int) {
>                 real_bkt = otx2_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
> -               cur_cyc = rte_rdtsc();
> +               cur_cyc = tim_cntvct();
>
>                 tim_ring->ring_start_cyc = cur_cyc -
>                                                 (real_bkt * tim_ring->tck_int);
> diff --git a/drivers/event/octeontx2/otx2_tim_worker.h b/drivers/event/octeontx2/otx2_tim_worker.h
> index aa69da96c..582b9c1b9 100644
> --- a/drivers/event/octeontx2/otx2_tim_worker.h
> +++ b/drivers/event/octeontx2/otx2_tim_worker.h
> @@ -132,7 +132,7 @@ tim_get_target_bucket(struct otx2_tim_ring *const tim_ring,
>                       const uint32_t rel_bkt, struct otx2_tim_bkt **bkt,
>                       struct otx2_tim_bkt **mirr_bkt)
>  {
> -       const uint64_t bkt_cyc = rte_rdtsc() - tim_ring->ring_start_cyc;
> +       const uint64_t bkt_cyc = tim_cntvct() - tim_ring->ring_start_cyc;
>         uint64_t bucket =
>                 rte_reciprocal_divide_u64(bkt_cyc, &tim_ring->fast_div) +
>                 rel_bkt;
> --
> 2.17.1
>