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dpif-netdev: Unique and sequential tx_qids.

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Currently tx_qid is equal to pmd->core_id. This leads to unexpected
behavior if pmd-cpu-mask different from '/(0*)(1|3|7)?(f*)/',
e.g. if core_ids are not sequential, or doesn't start from 0, or both.

Example:
	starting 2 pmd threads with 1 port, 2 rxqs per port,
	pmd-cpu-mask = 00000014 and let dev->real_n_txq = 2

	It that case pmd_1->tx_qid = 2, pmd_2->tx_qid = 4 and
	txq_needs_locking = true (if device hasn't ovs_numa_get_n_cores()+1
	queues).

	In that case, after truncating in netdev_dpdk_send__():
		'qid = qid % dev->real_n_txq;'
	pmd_1: qid = 2 % 2 = 0
	pmd_2: qid = 4 % 2 = 0

	So, both threads will call dpdk_queue_pkts() with same qid = 0.
	This is unexpected behavior if there is 2 tx queues in device.
	Queue #1 will not be used and both threads will lock queue #0
	on each send.

Fix that by using sequential tx_qids.

Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
This commit is contained in:
Ilya Maximets
2016-01-26 09:12:34 +03:00
committed by Daniele Di Proietto
parent ae7ad0a15e
commit 347ba9bb9b
1 changed files with 42 additions and 14 deletions
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56
lib/dpif-netdev.c
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@@ -434,7 +434,7 @@ struct dp_netdev_pmd_thread {
/* threads on same numa node. */
unsigned core_id; /* CPU core id of this pmd thread. */
int numa_id; /* numa node id of this pmd thread. */
int tx_qid; /* Queue id used by this pmd thread to
atomic_int tx_qid; /* Queue id used by this pmd thread to
* send packets on all netdevs */
struct ovs_mutex poll_mutex; /* Mutex for poll_list. */
@@ -1284,6 +1284,13 @@ get_port_by_name(struct dp_netdev *dp,
return ENOENT;
}
static int
get_n_pmd_threads(struct dp_netdev *dp)
{
/* There is one non pmd thread in dp->poll_threads */
return cmap_count(&dp->poll_threads) - 1;
}
static int
get_n_pmd_threads_on_numa(struct dp_netdev *dp, int numa_id)
{
@@ -2820,16 +2827,6 @@ dp_netdev_pmd_get_next(struct dp_netdev *dp, struct cmap_position *pos)
return next;
}
static int
core_id_to_qid(unsigned core_id)
{
if (core_id != NON_PMD_CORE_ID) {
return core_id;
} else {
return ovs_numa_get_n_cores();
}
}
/* Configures the 'pmd' based on the input argument. */
static void
dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
@@ -2838,10 +2835,14 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev *dp,
pmd->dp = dp;
pmd->index = index;
pmd->core_id = core_id;
pmd->tx_qid = core_id_to_qid(core_id);
pmd->numa_id = numa_id;
pmd->poll_cnt = 0;
atomic_init(&pmd->tx_qid,
(core_id == NON_PMD_CORE_ID)
? ovs_numa_get_n_cores()
: get_n_pmd_threads(dp));
ovs_refcount_init(&pmd->ref_cnt);
latch_init(&pmd->exit_latch);
atomic_init(&pmd->change_seq, PMD_INITIAL_SEQ);
@@ -2919,17 +2920,40 @@ dp_netdev_destroy_all_pmds(struct dp_netdev *dp)
}
}
/* Deletes all pmd threads on numa node 'numa_id'. */
/* Deletes all pmd threads on numa node 'numa_id' and
* fixes tx_qids of other threads to keep them sequential. */
static void
dp_netdev_del_pmds_on_numa(struct dp_netdev *dp, int numa_id)
{
struct dp_netdev_pmd_thread *pmd;
int n_pmds_on_numa, n_pmds;
int *free_idx, k = 0;
n_pmds_on_numa = get_n_pmd_threads_on_numa(dp, numa_id);
free_idx = xmalloc(n_pmds_on_numa * sizeof *free_idx);
CMAP_FOR_EACH (pmd, node, &dp->poll_threads) {
if (pmd->numa_id == numa_id) {
atomic_read_relaxed(&pmd->tx_qid, &free_idx[k]);
k++;
dp_netdev_del_pmd(dp, pmd);
}
}
n_pmds = get_n_pmd_threads(dp);
CMAP_FOR_EACH (pmd, node, &dp->poll_threads) {
int old_tx_qid;
atomic_read_relaxed(&pmd->tx_qid, &old_tx_qid);
if (old_tx_qid >= n_pmds) {
int new_tx_qid = free_idx[--k];
atomic_store_relaxed(&pmd->tx_qid, new_tx_qid);
}
}
free(free_idx);
}
/* Returns PMD thread from this numa node with fewer rx queues to poll.
@@ -3571,7 +3595,11 @@ dp_execute_cb(void *aux_, struct dp_packet **packets, int cnt,
case OVS_ACTION_ATTR_OUTPUT:
p = dp_netdev_lookup_port(dp, u32_to_odp(nl_attr_get_u32(a)));
if (OVS_LIKELY(p)) {
netdev_send(p->netdev, pmd->tx_qid, packets, cnt, may_steal);
int tx_qid;
atomic_read_relaxed(&pmd->tx_qid, &tx_qid);
netdev_send(p->netdev, tx_qid, packets, cnt, may_steal);
return;
}
break;