> -----Original Message-----
> From: [email protected] [mailto:ovs-dev-
> [email protected]] On Behalf Of Daniele Di Proietto
> Sent: 10 March 2017 04:13
> To: Ilya Maximets <[email protected]>
> Cc: [email protected]; Heetae Ahn <[email protected]>
> Subject: Re: [ovs-dev] [PATCH 2/4] dpif-netdev: Incremental
> addition/deletion of PMD threads.
>
> 2017-02-21 6:49 GMT-08:00 Ilya Maximets <[email protected]>:
> > Currently, change of 'pmd-cpu-mask' is very heavy operation.
> > It requires destroying of all the PMD threads and creating them back.
> > After that, all the threads will sleep until ports' redistribution
> > finished.
> >
> > This patch adds ability to not stop the datapath while adjusting
> > number/placement of PMD threads. All not affected threads will forward
> > traffic without any additional latencies.
> >
> > id-pool created for static tx queue ids to keep them sequential in a
> > flexible way. non-PMD thread will always have static_tx_qid = 0 as it
> > was before.
> >
> > Signed-off-by: Ilya Maximets <[email protected]>
>
> Thanks for the patch
>
> The idea looks good to me.
>
> I'm still looking at the code, and I have one comment below
>
Hi Ilya,
While reviewing the RFC Patch 4/4 in this series, I ran checkpatch.py over the
entire series. The tool returned the warning below for this patch. I don't plan
on reviewing this patch, but I thought I was send this as an FYI.
# ./checkpatch.py
ovs-dev-2-4-dpif-netdev-Incremental-addition-deletion-of-PMD-threads..patch
WARNING: Line length is >79-characters long
#66 FILE: lib/dpif-netdev.c:1088:
/* We need 1 Tx queue for each possible cpu core + 1 for non-PMD threads. */
Lines checked: 272, Warnings: 1, Errors: 0
> > ---
> > lib/dpif-netdev.c | 119
> +++++++++++++++++++++++++++++++++++++++++-------------
> > tests/pmd.at | 2 +-
> > 2 files changed, 91 insertions(+), 30 deletions(-)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index
> > 30907b7..6e575ab 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -48,6 +48,7 @@
> > #include "fat-rwlock.h"
> > #include "flow.h"
> > #include "hmapx.h"
> > +#include "id-pool.h"
> > #include "latch.h"
> > #include "netdev.h"
> > #include "netdev-vport.h"
> > @@ -241,6 +242,9 @@ struct dp_netdev {
> >
> > /* Stores all 'struct dp_netdev_pmd_thread's. */
> > struct cmap poll_threads;
> > + /* id pool for per thread static_tx_qid. */
> > + struct id_pool *tx_qid_pool;
> > + struct ovs_mutex tx_qid_pool_mutex;
> >
> > /* Protects the access of the 'struct dp_netdev_pmd_thread'
> > * instance for non-pmd thread. */ @@ -514,7 +518,7 @@ struct
> > dp_netdev_pmd_thread {
> > /* Queue id used by this pmd thread to send packets on all netdevs if
> > * XPS disabled for this netdev. All static_tx_qid's are unique and
> > less
> > * than 'cmap_count(dp->poll_threads)'. */
> > - const int static_tx_qid;
> > + uint32_t static_tx_qid;
> >
> > struct ovs_mutex port_mutex; /* Mutex for 'poll_list' and
> > 'tx_ports'. */
> > /* List of rx queues to poll. */
> > @@ -594,6 +598,8 @@ static struct dp_netdev_pmd_thread
> *dp_netdev_get_pmd(struct dp_netdev *dp,
> > unsigned
> > core_id); static struct dp_netdev_pmd_thread *
> > dp_netdev_pmd_get_next(struct dp_netdev *dp, struct cmap_position
> > *pos);
> > +static void dp_netdev_del_pmd(struct dp_netdev *dp,
> > + struct dp_netdev_pmd_thread *pmd);
> > static void dp_netdev_destroy_all_pmds(struct dp_netdev *dp, bool
> > non_pmd); static void dp_netdev_pmd_clear_ports(struct
> > dp_netdev_pmd_thread *pmd); static void
> > dp_netdev_add_port_tx_to_pmd(struct dp_netdev_pmd_thread *pmd,
> @@ -1077,10 +1083,17 @@ create_dp_netdev(const char *name, const
> struct dpif_class *class,
> > atomic_init(&dp->emc_insert_min, DEFAULT_EM_FLOW_INSERT_MIN);
> >
> > cmap_init(&dp->poll_threads);
> > +
> > + ovs_mutex_init(&dp->tx_qid_pool_mutex);
> > + /* We need 1 Tx queue for each possible cpu core + 1 for non-PMD
> threads. */
> > + dp->tx_qid_pool = id_pool_create(0, ovs_numa_get_n_cores() + 1);
> > +
> > ovs_mutex_init_recursive(&dp->non_pmd_mutex);
> > ovsthread_key_create(&dp->per_pmd_key, NULL);
> >
> > ovs_mutex_lock(&dp->port_mutex);
> > + /* non-PMD will be created before all other threads and will
> > + * allocate static_tx_qid = 0. */
> > dp_netdev_set_nonpmd(dp);
> >
> > error = do_add_port(dp, name,
> > dpif_netdev_port_open_type(dp->class,
> > @@ -1164,6 +1177,9 @@ dp_netdev_free(struct dp_netdev *dp)
> > dp_netdev_destroy_all_pmds(dp, true);
> > cmap_destroy(&dp->poll_threads);
> >
> > + ovs_mutex_destroy(&dp->tx_qid_pool_mutex);
> > + id_pool_destroy(dp->tx_qid_pool);
> > +
> > ovs_mutex_destroy(&dp->non_pmd_mutex);
> > ovsthread_key_delete(dp->per_pmd_key);
> >
> > @@ -3175,7 +3191,10 @@ reconfigure_pmd_threads(struct dp_netdev
> *dp)
> > {
> > struct dp_netdev_pmd_thread *pmd;
> > struct ovs_numa_dump *pmd_cores;
> > - bool changed = false;
> > + struct ovs_numa_info_core *core;
> > + struct hmapx to_delete = HMAPX_INITIALIZER(&to_delete);
> > + struct hmapx_node *node;
> > + int created = 0, deleted = 0;
> >
> > /* The pmd threads should be started only if there's a pmd port in the
> > * datapath. If the user didn't provide any "pmd-cpu-mask", we
> > start @@ -3188,45 +3207,62 @@ reconfigure_pmd_threads(struct
> dp_netdev *dp)
> > pmd_cores =
> ovs_numa_dump_n_cores_per_numa(NR_PMD_THREADS);
> > }
> >
> > - /* Check for changed configuration */
> > - if (ovs_numa_dump_count(pmd_cores) != cmap_count(&dp-
> >poll_threads) - 1) {
> > - changed = true;
> > - } else {
> > - CMAP_FOR_EACH (pmd, node, &dp->poll_threads) {
> > - if (pmd->core_id != NON_PMD_CORE_ID
> > - && !ovs_numa_dump_contains_core(pmd_cores,
> > - pmd->numa_id,
> > - pmd->core_id)) {
> > - changed = true;
> > - break;
> > - }
> > + /* Check for unwanted pmd threads */
> > + CMAP_FOR_EACH(pmd, node, &dp->poll_threads) {
> > + if (pmd->core_id != NON_PMD_CORE_ID
> > + && !ovs_numa_dump_contains_core(pmd_cores,
> > + pmd->numa_id,
> > + pmd->core_id)) {
> > + hmapx_add(&to_delete, pmd);
> > }
> > }
> > + HMAPX_FOR_EACH (node, &to_delete) {
> > + pmd = (struct dp_netdev_pmd_thread *) node->data;
> > + VLOG_INFO("PMD thread on numa_id: %d, core id: %2d destroyed.",
> > + pmd->numa_id, pmd->core_id);
> > + dp_netdev_del_pmd(dp, pmd);
> > + }
> > + deleted = hmapx_count(&to_delete);
> > + hmapx_destroy(&to_delete);
> >
> > - /* Destroy the old and recreate the new pmd threads. We don't
> perform an
> > - * incremental update because we would have to adjust 'static_tx_qid'.
> */
> > - if (changed) {
> > - struct ovs_numa_info_core *core;
> > - struct ovs_numa_info_numa *numa;
> > -
> > - /* Do not destroy the non pmd thread. */
> > - dp_netdev_destroy_all_pmds(dp, false);
> > - FOR_EACH_CORE_ON_DUMP (core, pmd_cores) {
> > - struct dp_netdev_pmd_thread *pmd = xzalloc(sizeof *pmd);
> > -
> > + /* Check for required new pmd threads */
> > + FOR_EACH_CORE_ON_DUMP(core, pmd_cores) {
> > + pmd = dp_netdev_get_pmd(dp, core->core_id);
> > + if (!pmd) {
> > + pmd = xzalloc(sizeof *pmd);
> > dp_netdev_configure_pmd(pmd, dp, core->core_id,
> > core->numa_id);
> > -
> > pmd->thread = ovs_thread_create("pmd", pmd_thread_main,
> > pmd);
> > + VLOG_INFO("PMD thread on numa_id: %d, core id: %2d created.",
> > + pmd->numa_id, pmd->core_id);
> > + created++;
> > + } else {
> > + dp_netdev_pmd_unref(pmd);
> > }
> > + }
> > +
> > + if (deleted || created) {
> > + struct ovs_numa_info_numa *numa;
> >
> > /* Log the number of pmd threads per numa node. */
> > FOR_EACH_NUMA_ON_DUMP (numa, pmd_cores) {
> > - VLOG_INFO("Created %"PRIuSIZE" pmd threads on numa node %d",
> > + VLOG_INFO("There are %"PRIuSIZE" pmd threads on numa node
> > + %d",
> > numa->n_cores, numa->numa_id);
> > }
> > }
> >
> > ovs_numa_dump_destroy(pmd_cores);
> > +
> > + if (deleted > created) {
> > + /* Static tx qids are not sequential now. Mark all threads for
> > + * reload to fix this. They will be reloaded after setting the new
> > + * txq numbers for ports to avoid using of not allocated queues by
> > + * old PMD threads. Newly created threads has no tx queues
> > + yet. */
>
> I'm not sure this is easy to maintain.
>
> What if we have something like:
>
> 1. delete old pmd threads
> 2. reconfigure txqs
> 3. add new pmd threads
>
> do you this it will be clearer?
>
> > + CMAP_FOR_EACH(pmd, node, &dp->poll_threads) {
> > + if (pmd->core_id != NON_PMD_CORE_ID) {
> > + pmd->need_reload = true;
> > + }
> > + }
> > + }
> > }
> >
> > static void
> > @@ -3541,6 +3577,29 @@ pmd_load_cached_ports(struct
> dp_netdev_pmd_thread *pmd)
> > }
> > }
> >
> > +static void
> > +pmd_alloc_static_tx_qid(struct dp_netdev_pmd_thread *pmd) {
> > + ovs_mutex_lock(&pmd->dp->tx_qid_pool_mutex);
> > + if (!id_pool_alloc_id(pmd->dp->tx_qid_pool, &pmd->static_tx_qid)) {
> > + VLOG_ERR("static_tx_qid allocation failed for PMD on core %2d"
> > + ", numa_id %d.", pmd->core_id, pmd->numa_id);
> > + OVS_NOT_REACHED();
> > + }
> > + ovs_mutex_unlock(&pmd->dp->tx_qid_pool_mutex);
> > +
> > + VLOG_DBG("static_tx_qid = %d allocated for PMD thread on core %2d"
> > + ", numa_id %d.", pmd->static_tx_qid, pmd->core_id,
> > +pmd->numa_id); }
> > +
> > +static void
> > +pmd_free_static_tx_qid(struct dp_netdev_pmd_thread *pmd) {
> > + ovs_mutex_lock(&pmd->dp->tx_qid_pool_mutex);
> > + id_pool_free_id(pmd->dp->tx_qid_pool, pmd->static_tx_qid);
> > + ovs_mutex_unlock(&pmd->dp->tx_qid_pool_mutex);
> > +}
> > +
> > static int
> > pmd_load_queues_and_ports(struct dp_netdev_pmd_thread *pmd,
> > struct polled_queue **ppoll_list) @@
> > -3586,6 +3645,7 @@ pmd_thread_main(void *f_)
> > dpdk_set_lcore_id(pmd->core_id);
> > poll_cnt = pmd_load_queues_and_ports(pmd, &poll_list);
> > reload:
> > + pmd_alloc_static_tx_qid(pmd);
> > emc_cache_init(&pmd->flow_cache);
> >
> > /* List port/core affinity */
> > @@ -3634,6 +3694,7 @@ reload:
> > dp_netdev_pmd_reload_done(pmd);
> >
> > emc_cache_uninit(&pmd->flow_cache);
> > + pmd_free_static_tx_qid(pmd);
> >
> > if (!exiting) {
> > goto reload;
> > @@ -3760,8 +3821,6 @@ dp_netdev_configure_pmd(struct
> dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
> > pmd->numa_id = numa_id;
> > pmd->need_reload = false;
> >
> > - *CONST_CAST(int *, &pmd->static_tx_qid) = cmap_count(&dp-
> >poll_threads);
> > -
> > ovs_refcount_init(&pmd->ref_cnt);
> > latch_init(&pmd->exit_latch);
> > pmd->reload_seq = seq_create();
> > @@ -3782,6 +3841,7 @@ dp_netdev_configure_pmd(struct
> dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
> > * actual thread created for NON_PMD_CORE_ID. */
> > if (core_id == NON_PMD_CORE_ID) {
> > emc_cache_init(&pmd->flow_cache);
> > + pmd_alloc_static_tx_qid(pmd);
> > }
> > cmap_insert(&dp->poll_threads, CONST_CAST(struct cmap_node *,
> &pmd->node),
> > hash_int(core_id, 0)); @@ -3824,6 +3884,7 @@
> > dp_netdev_del_pmd(struct dp_netdev *dp, struct
> dp_netdev_pmd_thread *pmd)
> > ovs_mutex_lock(&dp->non_pmd_mutex);
> > emc_cache_uninit(&pmd->flow_cache);
> > pmd_free_cached_ports(pmd);
> > + pmd_free_static_tx_qid(pmd);
> > ovs_mutex_unlock(&dp->non_pmd_mutex);
> > } else {
> > latch_set(&pmd->exit_latch);
> > diff --git a/tests/pmd.at b/tests/pmd.at index 5686bed..43bdb1b 100644
> > --- a/tests/pmd.at
> > +++ b/tests/pmd.at
> > @@ -38,7 +38,7 @@ dnl
> > dnl Whaits for creation of 'n_threads' or at least 1 thread if $1 not
> > dnl passed. Checking starts from line number 'line' in ovs-vswithd.log .
> > m4_define([CHECK_PMD_THREADS_CREATED], [
> > - PATTERN="Created [[0-9]]* pmd threads on numa node $2"
> > + PATTERN="There are [[0-9]]* pmd threads on numa node $2"
> > line_st=$3
> > if [[ -z "$line_st" ]]
> > then
> > --
> > 2.7.4
> >
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