pmd reloads are currently serialised in each steps calling reload_affected_pmds. Any pmd processing packets, waiting on a mutex etc... will make other pmd threads wait for a delay that can be undeterministic when syscalls adds up.
Switch to a little busy loop on the control thread using an atomic count. Signed-off-by: David Marchand <david.march...@redhat.com> --- lib/dpif-netdev.c | 43 ++++++++++++++++++++++++++++++------------- 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index 30774ed..b2b21fd 100644 --- a/lib/dpif-netdev.c +++ b/lib/dpif-netdev.c @@ -335,6 +335,9 @@ struct dp_netdev { /* The time that a packet can wait in output batch for sending. */ atomic_uint32_t tx_flush_interval; + /* Count of pmds currently reloading */ + atomic_count reloading_pmds; + /* Meters. */ struct ovs_mutex meter_locks[N_METER_LOCKS]; struct dp_meter *meters[MAX_METERS]; /* Meter bands. */ @@ -647,9 +650,6 @@ struct dp_netdev_pmd_thread { struct ovs_refcount ref_cnt; /* Every reference must be refcount'ed. */ struct cmap_node node; /* In 'dp->poll_threads'. */ - pthread_cond_t cond; /* For synchronizing pmd thread reload. */ - struct ovs_mutex cond_mutex; /* Mutex for condition variable. */ - /* Per thread exact-match cache. Note, the instance for cpu core * NON_PMD_CORE_ID can be accessed by multiple threads, and thusly * need to be protected by 'non_pmd_mutex'. Every other instance @@ -1525,6 +1525,8 @@ create_dp_netdev(const char *name, const struct dpif_class *class, atomic_init(&dp->emc_insert_min, DEFAULT_EM_FLOW_INSERT_MIN); atomic_init(&dp->tx_flush_interval, DEFAULT_TX_FLUSH_INTERVAL); + atomic_count_init(&dp->reloading_pmds, 0); + cmap_init(&dp->poll_threads); dp->pmd_rxq_assign_cyc = true; @@ -1754,11 +1756,8 @@ dp_netdev_reload_pmd__(struct dp_netdev_pmd_thread *pmd) return; } - ovs_mutex_lock(&pmd->cond_mutex); seq_change(pmd->reload_seq); atomic_store_relaxed(&pmd->reload, true); - ovs_mutex_cond_wait(&pmd->cond, &pmd->cond_mutex); - ovs_mutex_unlock(&pmd->cond_mutex); } static uint32_t @@ -4641,9 +4640,27 @@ rxq_scheduling(struct dp_netdev *dp, bool pinned) OVS_REQUIRES(dp->port_mutex) } static void +wait_reloading_pmds(struct dp_netdev *dp) +{ + while (atomic_count_get(&dp->reloading_pmds) != 0) { + } +} + +static void reload_affected_pmds(struct dp_netdev *dp) { struct dp_netdev_pmd_thread *pmd; + unsigned int pmd_count = 0; + + CMAP_FOR_EACH (pmd, node, &dp->poll_threads) { + if (pmd->core_id == NON_PMD_CORE_ID) { + continue; + } + if (pmd->need_reload) { + pmd_count++; + } + } + atomic_count_set(&dp->reloading_pmds, pmd_count); CMAP_FOR_EACH (pmd, node, &dp->poll_threads) { if (pmd->need_reload) { @@ -4652,6 +4669,10 @@ reload_affected_pmds(struct dp_netdev *dp) pmd->need_reload = false; } } + + if (pmd_count != 0) { + wait_reloading_pmds(dp); + } } static void @@ -5813,11 +5834,9 @@ dpif_netdev_enable_upcall(struct dpif *dpif) static void dp_netdev_pmd_reload_done(struct dp_netdev_pmd_thread *pmd) { - ovs_mutex_lock(&pmd->cond_mutex); atomic_store_relaxed(&pmd->reload, false); pmd->last_reload_seq = seq_read(pmd->reload_seq); - xpthread_cond_signal(&pmd->cond); - ovs_mutex_unlock(&pmd->cond_mutex); + atomic_count_dec(&pmd->dp->reloading_pmds); } /* Finds and refs the dp_netdev_pmd_thread on core 'core_id'. Returns @@ -5902,8 +5921,6 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev *dp, pmd->reload_seq = seq_create(); pmd->last_reload_seq = seq_read(pmd->reload_seq); atomic_init(&pmd->reload, false); - xpthread_cond_init(&pmd->cond, NULL); - ovs_mutex_init(&pmd->cond_mutex); ovs_mutex_init(&pmd->flow_mutex); ovs_mutex_init(&pmd->port_mutex); cmap_init(&pmd->flow_table); @@ -5946,8 +5963,6 @@ dp_netdev_destroy_pmd(struct dp_netdev_pmd_thread *pmd) cmap_destroy(&pmd->flow_table); ovs_mutex_destroy(&pmd->flow_mutex); seq_destroy(pmd->reload_seq); - xpthread_cond_destroy(&pmd->cond); - ovs_mutex_destroy(&pmd->cond_mutex); ovs_mutex_destroy(&pmd->port_mutex); free(pmd); } @@ -5967,7 +5982,9 @@ dp_netdev_del_pmd(struct dp_netdev *dp, struct dp_netdev_pmd_thread *pmd) ovs_mutex_unlock(&dp->non_pmd_mutex); } else { atomic_store_relaxed(&pmd->exit, true); + atomic_count_set(&dp->reloading_pmds, 1); dp_netdev_reload_pmd__(pmd); + wait_reloading_pmds(dp); xpthread_join(pmd->thread, NULL); } -- 1.8.3.1 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev