Yes, I think, this way is better. But it may be more simple
if we just keep all the dp_netdev_pmd_thread structures.
There is no need to search over all pmd threads on system.
Like this:
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 79c4612..8e4c025 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -2961,6 +2960,7 @@ dp_netdev_set_pmds_on_numa(struct dp_netdev *dp, int
numa_id)
* pmd threads for the numa node. */
if (!n_pmds) {
int can_have, n_unpinned, i;
+ struct dp_netdev_pmd_thread *pmd;
n_unpinned = ovs_numa_get_n_unpinned_cores_on_numa(numa_id);
if (!n_unpinned) {
@@ -2972,16 +2972,22 @@ dp_netdev_set_pmds_on_numa(struct dp_netdev *dp, int
numa_id)
/* If cpu mask is specified, uses all unpinned cores, otherwise
* tries creating NR_PMD_THREADS pmd threads. */
can_have = dp->pmd_cmask ? n_unpinned : MIN(n_unpinned,
NR_PMD_THREADS);
+ pmd = xzalloc(can_have * sizeof(*pmd));
for (i = 0; i < can_have; i++) {
- struct dp_netdev_pmd_thread *pmd = xzalloc(sizeof *pmd);
unsigned core_id = ovs_numa_get_unpinned_core_on_numa(numa_id);
-
- dp_netdev_configure_pmd(pmd, dp, i, core_id, numa_id);
+ dp_netdev_configure_pmd(&pmd[i], dp, i, core_id, numa_id);
+ }
+ /* The pmd thread code needs to see all the others configured pmd
+ * threads on the same numa node. That's why we call
+ * 'dp_netdev_configure_pmd()' on all the threads and then we actually
+ * start them. */
+ for (i = 0; i < can_have; i++) {
/* Each thread will distribute all devices rx-queues among
* themselves. */
- pmd->thread = ovs_thread_create("pmd", pmd_thread_main, pmd);
+ pmd[i].thread = ovs_thread_create("pmd", pmd_thread_main, &pmd[i]);
}
VLOG_INFO("Created %d pmd threads on numa node %d", can_have, numa_id);
+ dp_netdev_reload_pmds(dp);
}
}
On 24.07.2015 19:42, Daniele Di Proietto wrote:
> That's a bad race condition, thanks for reporting it!
>
> Regarding the fix, I agree that reloading the threads would
> restore the correct mapping, but it would still allow
> the threads to run with the incorrect mapping for a brief
> interval.
>
> How about postponing the actual threads creation until all
> the pmds are configured?
>
> Something like:
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 79c4612..26d9f1f 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -2961,6 +2961,7 @@ dp_netdev_set_pmds_on_numa(struct dp_netdev *dp, int
> numa_id)
> * pmd threads for the numa node. */
> if (!n_pmds) {
> int can_have, n_unpinned, i;
> + struct dp_netdev_pmd_thread *pmd;
>
> n_unpinned = ovs_numa_get_n_unpinned_cores_on_numa(numa_id);
> if (!n_unpinned) {
> @@ -2973,13 +2974,22 @@ dp_netdev_set_pmds_on_numa(struct dp_netdev *dp,
> int numa_id)
> * tries creating NR_PMD_THREADS pmd threads. */
> can_have = dp->pmd_cmask ? n_unpinned : MIN(n_unpinned,
> NR_PMD_THREADS);
> for (i = 0; i < can_have; i++) {
> - struct dp_netdev_pmd_thread *pmd = xzalloc(sizeof *pmd);
> unsigned core_id =
> ovs_numa_get_unpinned_core_on_numa(numa_id);
>
> + pmd = xzalloc(sizeof *pmd);
> dp_netdev_configure_pmd(pmd, dp, i, core_id, numa_id);
> - /* Each thread will distribute all devices rx-queues among
> - * themselves. */
> - pmd->thread = ovs_thread_create("pmd", pmd_thread_main, pmd);
> + }
> +
> + /* The pmd thread code needs to see all the others configured pmd
> + * threads on the same numa node. That's why we call
> + * 'dp_netdev_configure_pmd()' on all the threads and then we
> actually
> + * start them. */
> + CMAP_FOR_EACH (pmd, node, &dp->poll_threads) {
> + if (pmd->numa_id == numa_id) {
> + /* Each thread will distribute all devices rx-queues among
> + * themselves. */
> + pmd->thread = ovs_thread_create("pmd", pmd_thread_main,
> pmd);
> + }
> }
> VLOG_INFO("Created %d pmd threads on numa node %d", can_have,
> numa_id);
> }
>
>
> What do you think?
>
> Thanks!
>
> On 24/07/2015 12:18, "Ilya Maximets" <i.maxim...@samsung.com> wrote:
>
>> Currently pmd threads select queues in pmd_load_queues() according to
>> get_n_pmd_threads_on_numa(). This behavior leads to race between pmds,
>> beacause dp_netdev_set_pmds_on_numa() starts them one by one and
>> current number of threads changes incrementally.
>>
>> As a result we may have the following situation with 2 pmd threads:
>>
>> * dp_netdev_set_pmds_on_numa()
>> * pmd12 thread started. Currently only 1 pmd thread exists.
>> dpif_netdev(pmd12)|INFO|Core 1 processing port 'port_1'
>> dpif_netdev(pmd12)|INFO|Core 1 processing port 'port_2'
>> * pmd14 thread started. 2 pmd threads exists.
>> dpif_netdev|INFO|Created 2 pmd threads on numa node 0
>> dpif_netdev(pmd14)|INFO|Core 2 processing port 'port_2'
>>
>> We have:
>> core 1 --> port 1, port 2
>> core 2 --> port 2
>>
>> Fix this by reloading all pmds to get right port mapping.
>>
>> If we reload pmds, we'll have:
>> core 1 --> port 1
>> core 2 --> port 2
>>
>> Cc: Dyasly Sergey <s.dya...@samsung.com>
>> Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
>> ---
>> lib/dpif-netdev.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
>> index 2958d52..fd700f9 100644
>> --- a/lib/dpif-netdev.c
>> +++ b/lib/dpif-netdev.c
>> @@ -1127,10 +1127,9 @@ do_add_port(struct dp_netdev *dp, const char
>> *devname, const char *type,
>> ovs_refcount_init(&port->ref_cnt);
>> cmap_insert(&dp->ports, &port->node, hash_port_no(port_no));
>>
>> - if (netdev_is_pmd(netdev)) {
>> + if (netdev_is_pmd(netdev))
>> dp_netdev_set_pmds_on_numa(dp, netdev_get_numa_id(netdev));
>> - dp_netdev_reload_pmds(dp);
>> - }
>> +
>> seq_change(dp->port_seq);
>>
>> return 0;
>> @@ -2978,6 +2977,7 @@ dp_netdev_set_pmds_on_numa(struct dp_netdev *dp,
>> int numa_id)
>> pmd->thread = ovs_thread_create("pmd", pmd_thread_main, pmd);
>> }
>> VLOG_INFO("Created %d pmd threads on numa node %d", can_have,
>> numa_id);
>> + dp_netdev_reload_pmds(dp);
>> }
>> }
>>
>> --
>> 2.1.4
>>
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>
>
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