Sorry,
without dp_netdev_reload_pmds(dp) at the end.
On 27.07.2015 10:58, Ilya Maximets wrote:
> 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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