[ovs-dev] [PATCH 2/4] dpif-netdev: Incremental addition/deletion of PMD threads.
Ilya Maximets
i.maximets at samsung.com
Tue Feb 21 14:49:26 UTC 2017
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 <i.maximets at samsung.com>
---
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. */
+ 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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