[ovs-dev] [PATCH v6 2/4] dpif-netdev: Add parameters to configure PMD auto load balance.
Stokes, Ian
ian.stokes at intel.com
Fri Jan 15 17:56:28 UTC 2021
> On 15/01/2021 17:22, Ilya Maximets wrote:
> > On 12/21/20 2:10 PM, Kevin Traynor wrote:
> >> From: Christophe Fontaine <cfontain at redhat.com>
> >>
> >> Two important parts of how PMD auto load balance operates are how
> >> loaded a core needs to be and how much improvement is estimated
> >> before a PMD auto load balance can trigger.
> >>
> >> Previously they were hardcoded to 95% loaded and 25% variance
> >> improvement.
> >>
> >> These default values may not be suitable for all use cases and
> >> we may want to use a more (or less) aggressive rebalance, either
> >> on the pmd load threshold or on the minimum variance improvement
> >> threshold.
> >>
> >> The defaults are not changed, but "pmd-auto-lb-pmd-load" and
> >> "pmd-auto-lb-improvement" parameters are added to override the
> >> defaults.
> >>
> >> $ ovs-vsctl set open_vswitch . other_config:pmd-auto-lb-pmd-load="70"
> >
> > Sorry for the late review, but this name is bothering me.
> > Especially the repeated 'pmd'. And it's also unclear what this parameter
> > means by only looking at the name.
> >
> > Maybe it's better to rename it to 'pmd-auto-lb-load-threshold'?
> >
>
> I think we had an additional "threshold" at some point but it was
> getting long. Your suggestion reads well to me.
>
> >> $ ovs-vsctl set open_vswitch . other_config:pmd-auto-lb-improvement="20"
> >
> > And following the logic, just to be consistent, this one could be renamed
> > to 'pmd-auto-lb-improvement-threshold'.
> >
>
> +1
>
++1
> > Kevin, Ian, what do you think?
> >
> > I can replace on commit.
> >
Sounds good to me.
BR
Ian
>
> Thanks, or I can re-spin, just let me know.
>
> >>
> >> Signed-off-by: Christophe Fontaine <cfontain at redhat.com>
> >> Co-Authored-by: Kevin Traynor <ktraynor at redhat.com>
> >> Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
> >> Acked-by: David Marchand <david.marchand at redhat.com>
> >> ---
> >> NEWS | 1 +
> >> lib/dpif-netdev.c | 54 +++++++++++++++++++++++++++++++++++++-------
> >> vswitchd/vswitch.xml | 29 ++++++++++++++++++++++--
> >> 3 files changed, 74 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/NEWS b/NEWS
> >> index 7e291a180..7994e434d 100644
> >> --- a/NEWS
> >> +++ b/NEWS
> >> @@ -17,4 +17,5 @@ Post-v2.14.0
> >> * New 'options:dpdk-vf-mac' field for DPDK interface of VF ports,
> >> that allows configuring the MAC address of a VF representor.
> >> + * Add parameters to configure PMD auto load balance behaviour.
> >> - The environment variable OVS_UNBOUND_CONF, if set, is now used
> >> as the DNS resolver's (unbound) configuration file.
> >> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> >> index d19d5bbff..bf2112815 100644
> >> --- a/lib/dpif-netdev.c
> >> +++ b/lib/dpif-netdev.c
> >> @@ -86,7 +86,7 @@ VLOG_DEFINE_THIS_MODULE(dpif_netdev);
> >>
> >> /* Auto Load Balancing Defaults */
> >> -#define ALB_ACCEPTABLE_IMPROVEMENT 25
> >> -#define ALB_PMD_LOAD_THRESHOLD 95
> >> -#define ALB_PMD_REBALANCE_POLL_INTERVAL 1 /* 1 Min */
> >> +#define ALB_IMPROVEMENT_THRESHOLD 25
> >> +#define ALB_LOAD_THRESHOLD 95
> >> +#define ALB_REBALANCE_INTERVAL 1 /* 1 Min */
> >> #define MIN_TO_MSEC 60000
> >>
> >> @@ -301,4 +301,6 @@ struct pmd_auto_lb {
> >> uint64_t rebalance_intvl;
> >> uint64_t rebalance_poll_timer;
> >> + uint8_t rebalance_improve_thresh;
> >> + atomic_uint8_t rebalance_load_thresh;
> >> };
> >>
> >> @@ -4205,4 +4207,5 @@ set_pmd_auto_lb(struct dp_netdev *dp)
> >> struct dp_netdev_pmd_thread *pmd;
> >> struct pmd_auto_lb *pmd_alb = &dp->pmd_alb;
> >> + uint8_t rebalance_load_thresh;
> >>
> >> bool enable_alb = false;
> >> @@ -4234,7 +4237,14 @@ set_pmd_auto_lb(struct dp_netdev *dp)
> >> pmd_alb->is_enabled = enable_alb;
> >> if (pmd_alb->is_enabled) {
> >> + atomic_read_relaxed(&pmd_alb->rebalance_load_thresh,
> >> + &rebalance_load_thresh);
> >> VLOG_INFO("PMD auto load balance is enabled "
> >> - "interval %"PRIu64" mins",
> >> - pmd_alb->rebalance_intvl / MIN_TO_MSEC);
> >> + "interval %"PRIu64" mins, "
> >> + "pmd load threshold %"PRIu8"%%, "
> >> + "improvement threshold %"PRIu8"%%",
> >> + pmd_alb->rebalance_intvl / MIN_TO_MSEC,
> >> + rebalance_load_thresh,
> >> + pmd_alb->rebalance_improve_thresh);
> >> +
> >> } else {
> >> pmd_alb->rebalance_poll_timer = 0;
> >> @@ -4260,4 +4270,6 @@ dpif_netdev_set_config(struct dpif *dpif, const
> struct smap *other_config)
> >> uint32_t tx_flush_interval, cur_tx_flush_interval;
> >> uint64_t rebalance_intvl;
> >> + uint8_t rebalance_load, cur_rebalance_load;
> >> + uint8_t rebalance_improve;
> >>
> >> tx_flush_interval = smap_get_int(other_config, "tx-flush-interval",
> >> @@ -4337,5 +4349,5 @@ dpif_netdev_set_config(struct dpif *dpif, const
> struct smap *other_config)
> >>
> >> rebalance_intvl = smap_get_int(other_config, "pmd-auto-lb-rebal-
> interval",
> >> - ALB_PMD_REBALANCE_POLL_INTERVAL);
> >> + ALB_REBALANCE_INTERVAL);
> >>
> >> /* Input is in min, convert it to msec. */
> >> @@ -4349,4 +4361,27 @@ dpif_netdev_set_config(struct dpif *dpif, const
> struct smap *other_config)
> >> }
> >>
> >> + rebalance_improve = smap_get_int(other_config, "pmd-auto-lb-
> improvement",
> >> + ALB_IMPROVEMENT_THRESHOLD);
> >> + if (rebalance_improve > 100) {
> >> + rebalance_improve = ALB_IMPROVEMENT_THRESHOLD;
> >> + }
> >> + if (rebalance_improve != pmd_alb->rebalance_improve_thresh) {
> >> + pmd_alb->rebalance_improve_thresh = rebalance_improve;
> >> + VLOG_INFO("PMD auto load balance improvement threshold set to "
> >> + "%"PRIu8"%%\n", rebalance_improve);
> >> + }
> >> +
> >> + rebalance_load = smap_get_int(other_config, "pmd-auto-lb-pmd-load",
> >> + ALB_LOAD_THRESHOLD);
> >> + if (rebalance_load > 100) {
> >> + rebalance_load = ALB_LOAD_THRESHOLD;
> >> + }
> >> + atomic_read_relaxed(&pmd_alb->rebalance_load_thresh,
> &cur_rebalance_load);
> >> + if (rebalance_load != cur_rebalance_load) {
> >> + atomic_store_relaxed(&pmd_alb->rebalance_load_thresh,
> >> + rebalance_load);
> >> + VLOG_INFO("PMD auto load balance pmd load threshold set to "
> >> + "%"PRIu8"%%\n", rebalance_load);
> >> + }
> >> set_pmd_auto_lb(dp);
> >> return 0;
> >> @@ -5677,5 +5712,5 @@ pmd_rebalance_dry_run(struct dp_netdev *dp)
> >> ((curr_variance - new_variance) * 100) / curr_variance;
> >> }
> >> - if (improvement < ALB_ACCEPTABLE_IMPROVEMENT) {
> >> + if (improvement < dp->pmd_alb.rebalance_improve_thresh) {
> >> ret = false;
> >> }
> >> @@ -8712,4 +8747,5 @@ dp_netdev_pmd_try_optimize(struct
> dp_netdev_pmd_thread *pmd,
> >> if (pmd->ctx.now > pmd->rxq_next_cycle_store) {
> >> uint64_t curr_tsc;
> >> + uint8_t rebalance_load_trigger;
> >> struct pmd_auto_lb *pmd_alb = &pmd->dp->pmd_alb;
> >> if (pmd_alb->is_enabled && !pmd->isolated
> >> @@ -8728,5 +8764,7 @@ dp_netdev_pmd_try_optimize(struct
> dp_netdev_pmd_thread *pmd,
> >> }
> >>
> >> - if (pmd_load >= ALB_PMD_LOAD_THRESHOLD) {
> >> + atomic_read_relaxed(&pmd_alb->rebalance_load_thresh,
> >> + &rebalance_load_trigger);
> >> + if (pmd_load >= rebalance_load_trigger) {
> >> atomic_count_inc(&pmd->pmd_overloaded);
> >> } else {
> >> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
> >> index 89a876796..76d528ea7 100644
> >> --- a/vswitchd/vswitch.xml
> >> +++ b/vswitchd/vswitch.xml
> >> @@ -654,6 +654,6 @@
> >> <p>
> >> Configures PMD Auto Load Balancing that allows automatic assignment
> of
> >> - RX queues to PMDs if any of PMDs is overloaded (i.e. processing cycles
> >> - > 95%).
> >> + RX queues to PMDs if any of PMDs is overloaded (i.e. a processing
> >> + cycles > <ref column="other_config" key="pmd-auto-lb-pmd-load"/>).
> >> </p>
> >> <p>
> >> @@ -691,4 +691,29 @@
> >> </p>
> >> </column>
> >> + <column name="other_config" key="pmd-auto-lb-pmd-load"
> >> + type='{"type": "integer", "minInteger": 0, "maxInteger": 100}'>
> >> + <p>
> >> + Specifies the minimum pmd load threshold (% of used cycled) of
> >> + any non-isolated pmds when a PMD auto load balance may be
> triggered.
> >> + </p>
> >> + <p>
> >> + The default value is <code>95%</code>.
> >> + </p>
> >> + </column>
> >> + <column name="other_config" key="pmd-auto-lb-improvement"
> >> + type='{"type": "integer", "minInteger": 0, "maxInteger": 100}'>
> >> + <p>
> >> + Specifies the minimum evaluated % improvement in load distribution
> >> + across the non-isolated pmds that will allow a PMD auto load balance
> >> + to occur.
> >> + </p>
> >> + <p>
> >> + Note, setting this parameter to 0 will always allow an auto load
> >> + balance to occur regardless of estimated improvement or not.
> >> + </p>
> >> + <p>
> >> + The default value is <code>25%</code>.
> >> + </p>
> >> + </column>
> >> <column name="other_config" key="userspace-tso-enable"
> >> type='{"type": "boolean"}'>
> >>
> >
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