Re: [PATCH v3 1/2] xen: credit1: trace vCPU boost/unboost

[George Dunlap <george.dunlap@citrix.com>]

On 12/02/16 16:29, Dario Faggioli wrote:
> Add tracepoints and a performance counter for
> boosting and unboosting in Credit1.
> 
> Note that they (the trace points) do not cover
> the case of the idle vCPU being boosted to run
> a tasklet, as there already is
> TRC_CSCHED_SCHED_TASKLET for that.
> 
> Signed-off-by:  Dario Faggioli <dario.faggioli@citrix.com>

Reviewed-by: George Dunlap <george.dunlap@citrix.com>

> ---
> Cc: George Dunlap <george.dunlap@eu.citrix.com>
> ---
>  xen/common/sched_credit.c    |    8 ++++++++
>  xen/include/xen/perfc_defn.h |    1 +
>  2 files changed, 9 insertions(+)
> 
> diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
> index 671bbee..5708701 100644
> --- a/xen/common/sched_credit.c
> +++ b/xen/common/sched_credit.c
> @@ -126,6 +126,8 @@
>  #define TRC_CSCHED_STOLEN_VCPU   TRC_SCHED_CLASS_EVT(CSCHED, 4)
>  #define TRC_CSCHED_PICKED_CPU    TRC_SCHED_CLASS_EVT(CSCHED, 5)
>  #define TRC_CSCHED_TICKLE        TRC_SCHED_CLASS_EVT(CSCHED, 6)
> +#define TRC_CSCHED_BOOST_START   TRC_SCHED_CLASS_EVT(CSCHED, 7)
> +#define TRC_CSCHED_BOOST_END     TRC_SCHED_CLASS_EVT(CSCHED, 8)
>  
>  
>  /*
> @@ -856,7 +858,11 @@ csched_vcpu_acct(struct csched_private *prv, unsigned int cpu)
>       * amount of CPU resources and should no longer be boosted.
>       */
>      if ( svc->pri == CSCHED_PRI_TS_BOOST )
> +    {
>          svc->pri = CSCHED_PRI_TS_UNDER;
> +        TRACE_2D(TRC_CSCHED_BOOST_END, svc->sdom->dom->domain_id,
> +                 svc->vcpu->vcpu_id);
> +    }
>  
>      /*
>       * Update credits
> @@ -1023,6 +1029,8 @@ csched_vcpu_wake(const struct scheduler *ops, struct vcpu *vc)
>      if ( svc->pri == CSCHED_PRI_TS_UNDER &&
>           !test_bit(CSCHED_FLAG_VCPU_PARKED, &svc->flags) )
>      {
> +        TRACE_2D(TRC_CSCHED_BOOST_START, vc->domain->domain_id, vc->vcpu_id);
> +        SCHED_STAT_CRANK(vcpu_boost);
>          svc->pri = CSCHED_PRI_TS_BOOST;
>      }
>  
> diff --git a/xen/include/xen/perfc_defn.h b/xen/include/xen/perfc_defn.h
> index 76ee803..21c1e0b 100644
> --- a/xen/include/xen/perfc_defn.h
> +++ b/xen/include/xen/perfc_defn.h
> @@ -40,6 +40,7 @@ PERFCOUNTER(acct_reorder,           "csched: acct_reorder")
>  PERFCOUNTER(acct_min_credit,        "csched: acct_min_credit")
>  PERFCOUNTER(acct_vcpu_active,       "csched: acct_vcpu_active")
>  PERFCOUNTER(acct_vcpu_idle,         "csched: acct_vcpu_idle")
> +PERFCOUNTER(vcpu_boost,             "csched: vcpu_boost")
>  PERFCOUNTER(vcpu_park,              "csched: vcpu_park")
>  PERFCOUNTER(vcpu_unpark,            "csched: vcpu_unpark")
>  PERFCOUNTER(load_balance_idle,      "csched: load_balance_idle")
>