Re: [ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[David Marchand]

On Tue, Jun 25, 2019 at 3:47 PM Ilya Maximets 
wrote:

> On 23.05.2019 17:23, David Marchand wrote:
> > When swapping queues from a pmd thread to another (q0 polled by pmd0/q1
> > polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
> > "Step 5" puts both pmds to sleep waiting for the control thread to wake
> > them up later.
> >
> > Prefer to make them spin in such a case to avoid sleeping an
> > undeterministic amount of time.
> >
> > Signed-off-by: David Marchand 
> > Acked-by: Eelco Chaudron 
> > ---
> >  lib/dpif-netdev.c | 47 ++-
> >  1 file changed, 42 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index 23cf6a6..243c1ce 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
> >  struct seq *reload_seq;
> >  uint64_t last_reload_seq;
> >  atomic_bool reload; /* Do we need to reload ports? */
> > +atomic_bool wait_for_reload;/* Can we busy wait for the next
> reload? */
> >  atomic_bool exit;   /* For terminating the pmd thread.
> */
> >  pthread_t thread;
> >  unsigned core_id;   /* CPU core id of this pmd thread.
> */
> > @@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
> >  HMAP_FOR_EACH_SAFE (poll, poll_next, node, >poll_list) {
> >  if (poll->rxq->pmd != pmd) {
> >  dp_netdev_del_rxq_from_pmd(pmd, poll);
> > +
> > +/* This pmd might sleep after this step reload if it
> has no
> > + * rxq remaining. Can we tell it to busy wait for new
> rxq at
> > + * Step 6 ? */
> > +if (hmap_count(>poll_list) == 0) {
> > +HMAP_FOR_EACH (port, node, >ports) {
> > +int qid;
> > +
> > +if (!netdev_is_pmd(port->netdev)) {
> > +continue;
> > +}
> > +
> > +for (qid = 0; qid < port->n_rxq; qid++) {
> > +struct dp_netdev_rxq *q = >rxqs[qid];
> > +
> > +if (q->pmd == pmd) {
> > +
> atomic_store_relaxed(>pmd->wait_for_reload,
> > + true);
> > +break;
>
> 8 levels of indentation make me feel frustrated.
>
> What do you think about following incremental:
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 34ac09322..adc095579 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -4810,6 +4834,7 @@ reconfigure_datapath(struct dp_netdev *dp)
>  {
>  struct dp_netdev_pmd_thread *pmd;
>  struct dp_netdev_port *port;
> +struct hmapx busy_threads = HMAPX_INITIALIZER(_threads);
>  int wanted_txqs;
>
>  dp->last_reconfigure_seq = seq_read(dp->reconfigure_seq);
> @@ -4895,6 +4920,20 @@ reconfigure_datapath(struct dp_netdev *dp)
>  rxq_scheduling(dp, false);
>
>  /* Step 5: Remove queues not compliant with new scheduling. */
> +
> +/* Count all the threads that will have at least one queue to poll. */
> +HMAP_FOR_EACH (port, node, >ports) {
> +for (int qid = 0; qid < port->n_rxq; qid++) {
> +struct dp_netdev_rxq *q = >rxqs[qid];
> +
> +if (q->pmd) {
> +hmapx_add(_threads, q->pmd);
> +}
> +}
> +}
> +
> +/* Remove queues not compliant with new scheduling.  Asking busy
> threads
> + * to busy-wait for a new queue assignment. */
>

Not a fan of this comment, looks duplicated with the one before that
announces what Step 5 does.
Plus, we have another one later about the busy wait.

I would take your suggestion but without this comment here.



 CMAP_FOR_EACH (pmd, node, >poll_threads) {
>  struct rxq_poll *poll, *poll_next;
>
> @@ -4903,37 +4942,20 @@ reconfigure_datapath(struct dp_netdev *dp)
>  if (poll->rxq->pmd != pmd) {
>  dp_netdev_del_rxq_from_pmd(pmd, poll);
>
> -/* This pmd might sleep after this step reload if it has
> no
> - * rxq remaining. Can we tell it to busy wait for new rxq
> at
> - * Step 6 ? */
> -if (hmap_count(>poll_list) == 0) {
> -HMAP_FOR_EACH (port, node, >ports) {
> -int qid;
> -
> -if (!netdev_is_pmd(port->netdev)) {
> -continue;
> -}
> -
> -for (qid = 0; qid < port->n_rxq; qid++) {
> -struct dp_netdev_rxq *q = >rxqs[qid];
> -
> -if (q->pmd == pmd) {
> -
> atomic_store_relaxed(>pmd->wait_for_reload,
> - true);
> -break;
> -}
> - 

Re: [ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[Ilya Maximets]

On 23.05.2019 17:23, David Marchand wrote:
> When swapping queues from a pmd thread to another (q0 polled by pmd0/q1
> polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
> "Step 5" puts both pmds to sleep waiting for the control thread to wake
> them up later.
> 
> Prefer to make them spin in such a case to avoid sleeping an
> undeterministic amount of time.
> 
> Signed-off-by: David Marchand 
> Acked-by: Eelco Chaudron 
> ---
>  lib/dpif-netdev.c | 47 ++-
>  1 file changed, 42 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 23cf6a6..243c1ce 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
>  struct seq *reload_seq;
>  uint64_t last_reload_seq;
>  atomic_bool reload; /* Do we need to reload ports? */
> +atomic_bool wait_for_reload;/* Can we busy wait for the next reload? 
> */
>  atomic_bool exit;   /* For terminating the pmd thread. */
>  pthread_t thread;
>  unsigned core_id;   /* CPU core id of this pmd thread. */
> @@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
>  HMAP_FOR_EACH_SAFE (poll, poll_next, node, >poll_list) {
>  if (poll->rxq->pmd != pmd) {
>  dp_netdev_del_rxq_from_pmd(pmd, poll);
> +
> +/* This pmd might sleep after this step reload if it has no
> + * rxq remaining. Can we tell it to busy wait for new rxq at
> + * Step 6 ? */
> +if (hmap_count(>poll_list) == 0) {
> +HMAP_FOR_EACH (port, node, >ports) {
> +int qid;
> +
> +if (!netdev_is_pmd(port->netdev)) {
> +continue;
> +}
> +
> +for (qid = 0; qid < port->n_rxq; qid++) {
> +struct dp_netdev_rxq *q = >rxqs[qid];
> +
> +if (q->pmd == pmd) {
> +
> atomic_store_relaxed(>pmd->wait_for_reload,
> + true);
> +break;

8 levels of indentation make me feel frustrated.

What do you think about following incremental:

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 34ac09322..adc095579 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -4810,6 +4834,7 @@ reconfigure_datapath(struct dp_netdev *dp)
 {
 struct dp_netdev_pmd_thread *pmd;
 struct dp_netdev_port *port;
+struct hmapx busy_threads = HMAPX_INITIALIZER(_threads);
 int wanted_txqs;
 
 dp->last_reconfigure_seq = seq_read(dp->reconfigure_seq);
@@ -4895,6 +4920,20 @@ reconfigure_datapath(struct dp_netdev *dp)
 rxq_scheduling(dp, false);
 
 /* Step 5: Remove queues not compliant with new scheduling. */
+
+/* Count all the threads that will have at least one queue to poll. */
+HMAP_FOR_EACH (port, node, >ports) {
+for (int qid = 0; qid < port->n_rxq; qid++) {
+struct dp_netdev_rxq *q = >rxqs[qid];
+
+if (q->pmd) {
+hmapx_add(_threads, q->pmd);
+}
+}
+}
+
+/* Remove queues not compliant with new scheduling.  Asking busy threads
+ * to busy-wait for a new queue assignment. */
 CMAP_FOR_EACH (pmd, node, >poll_threads) {
 struct rxq_poll *poll, *poll_next;
 
@@ -4903,37 +4942,20 @@ reconfigure_datapath(struct dp_netdev *dp)
 if (poll->rxq->pmd != pmd) {
 dp_netdev_del_rxq_from_pmd(pmd, poll);
 
-/* This pmd might sleep after this step reload if it has no
- * rxq remaining. Can we tell it to busy wait for new rxq at
- * Step 6 ? */
-if (hmap_count(>poll_list) == 0) {
-HMAP_FOR_EACH (port, node, >ports) {
-int qid;
-
-if (!netdev_is_pmd(port->netdev)) {
-continue;
-}
-
-for (qid = 0; qid < port->n_rxq; qid++) {
-struct dp_netdev_rxq *q = >rxqs[qid];
-
-if (q->pmd == pmd) {
-atomic_store_relaxed(>pmd->wait_for_reload,
- true);
-break;
-}
-}
-
-if (qid != port->n_rxq) {
-break;
-}
-}
+/* This thread might sleep after this step if it has no rxq
+ * remaining.  Tell it to busy wait for a new assignment
+ * if it has at least one scheduled queue. */
+if (hmap_count(>poll_list) == 0
+

Re: [ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[Ian Stokes]

On 6/20/2019 3:31 PM, David Marchand wrote:




On Wed, Jun 19, 2019 at 3:40 PM Ian Stokes > wrote:


On 5/23/2019 3:23 PM, David Marchand wrote:
 > When swapping queues from a pmd thread to another (q0 polled by
pmd0/q1
 > polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
 > "Step 5" puts both pmds to sleep waiting for the control thread
to wake
 > them up later.
 >
 > Prefer to make them spin in such a case to avoid sleeping an
 > undeterministic amount of time.
 >
 > Signed-off-by: David Marchand mailto:david.march...@redhat.com>>
 > Acked-by: Eelco Chaudron mailto:echau...@redhat.com>>
 > ---
 >   lib/dpif-netdev.c | 47
++-
 >   1 file changed, 42 insertions(+), 5 deletions(-)
 >
 > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
 > index 23cf6a6..243c1ce 100644
 > --- a/lib/dpif-netdev.c
 > +++ b/lib/dpif-netdev.c
 > @@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
 >       struct seq *reload_seq;
 >       uint64_t last_reload_seq;
 >       atomic_bool reload;             /* Do we need to reload
ports? */
 > +    atomic_bool wait_for_reload;    /* Can we busy wait for the
next reload? */
 >       atomic_bool exit;               /* For terminating the pmd
thread. */
 >       pthread_t thread;
 >       unsigned core_id;               /* CPU core id of this pmd
thread. */
 > @@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
 >           HMAP_FOR_EACH_SAFE (poll, poll_next, node,
>poll_list) {
 >               if (poll->rxq->pmd != pmd) {
 >                   dp_netdev_del_rxq_from_pmd(pmd, poll);

I'm a little confused by the block below.

 > +
 > +                /* This pmd might sleep after this step reload
if it has no
 > +                 * rxq remaining. Can we tell it to busy wait
for new rxq at
 > +                 * Step 6 ? */

So whats the typical cases we target here, I would think this would
occur if PMDs have been isolated and there are no non isolated queues
available for the rxq to be assigned to?


It can happen in any situation when the rebalance code decides to 
reassign rxqs in a way that, for a given pmd, the old polling list 
intersection with the new polling list is null.
Because of this null intersection, between step 5 and step 6 reload 
notifications, the pmd sleeps until it is woken on the poll_block().




Ah, ok, now that makes a little more sense. From what i've seen, the 
rest of the series look ok, I just want to run a few more tests with 
this scenario in mind.





 > +                if (hmap_count(>poll_list) == 0) {
 > +                    HMAP_FOR_EACH (port, node, >ports) {
 > +                        int qid;
 > +
 > +                        if (!netdev_is_pmd(port->netdev)) {
 > +                            continue;
 > +                        }
 > +
 > +                        for (qid = 0; qid < port->n_rxq; qid++) {
 > +                            struct dp_netdev_rxq *q =
>rxqs[qid];
 > +
 > +                            if (q->pmd == pmd) {
 > +   
atomic_store_relaxed(>pmd->wait_for_reload,

 > +                                                     true);

I was a little confused here, are we marking wait_for_reload true here
so that reload in step 6 will handle any new assignment? Does this not
put it in the busy-wait state already here in step 5? It's just from
reading the comment it looked like busy wait status was expected in
step
6 rather than here.


Nop, we are in step 5, so yes, the comment should say "until" instead of 
"at" ?


Perfect.

Thanks
Ian



--
David Marchand


___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Re: [ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[David Marchand]

On Wed, Jun 19, 2019 at 3:40 PM Ian Stokes  wrote:

> On 5/23/2019 3:23 PM, David Marchand wrote:
> > When swapping queues from a pmd thread to another (q0 polled by pmd0/q1
> > polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
> > "Step 5" puts both pmds to sleep waiting for the control thread to wake
> > them up later.
> >
> > Prefer to make them spin in such a case to avoid sleeping an
> > undeterministic amount of time.
> >
> > Signed-off-by: David Marchand 
> > Acked-by: Eelco Chaudron 
> > ---
> >   lib/dpif-netdev.c | 47 ++-
> >   1 file changed, 42 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index 23cf6a6..243c1ce 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
> >   struct seq *reload_seq;
> >   uint64_t last_reload_seq;
> >   atomic_bool reload; /* Do we need to reload ports? */
> > +atomic_bool wait_for_reload;/* Can we busy wait for the next
> reload? */
> >   atomic_bool exit;   /* For terminating the pmd thread.
> */
> >   pthread_t thread;
> >   unsigned core_id;   /* CPU core id of this pmd thread.
> */
> > @@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
> >   HMAP_FOR_EACH_SAFE (poll, poll_next, node, >poll_list) {
> >   if (poll->rxq->pmd != pmd) {
> >   dp_netdev_del_rxq_from_pmd(pmd, poll);
>
> I'm a little confused by the block below.
>
> > +
> > +/* This pmd might sleep after this step reload if it
> has no
> > + * rxq remaining. Can we tell it to busy wait for new
> rxq at
> > + * Step 6 ? */
>
> So whats the typical cases we target here, I would think this would
> occur if PMDs have been isolated and there are no non isolated queues
> available for the rxq to be assigned to?
>

It can happen in any situation when the rebalance code decides to reassign
rxqs in a way that, for a given pmd, the old polling list intersection with
the new polling list is null.
Because of this null intersection, between step 5 and step 6 reload
notifications, the pmd sleeps until it is woken on the poll_block().



> > +if (hmap_count(>poll_list) == 0) {
> > +HMAP_FOR_EACH (port, node, >ports) {
> > +int qid;
> > +
> > +if (!netdev_is_pmd(port->netdev)) {
> > +continue;
> > +}
> > +
> > +for (qid = 0; qid < port->n_rxq; qid++) {
> > +struct dp_netdev_rxq *q = >rxqs[qid];
> > +
> > +if (q->pmd == pmd) {
> > +
> atomic_store_relaxed(>pmd->wait_for_reload,
> > + true);
>
> I was a little confused here, are we marking wait_for_reload true here
> so that reload in step 6 will handle any new assignment? Does this not
> put it in the busy-wait state already here in step 5? It's just from
> reading the comment it looked like busy wait status was expected in step
> 6 rather than here.
>

Nop, we are in step 5, so yes, the comment should say "until" instead of
"at" ?


-- 
David Marchand
___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Re: [ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[Ian Stokes]

On 5/23/2019 3:23 PM, David Marchand wrote:

When swapping queues from a pmd thread to another (q0 polled by pmd0/q1
polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
"Step 5" puts both pmds to sleep waiting for the control thread to wake
them up later.

Prefer to make them spin in such a case to avoid sleeping an
undeterministic amount of time.

Signed-off-by: David Marchand 
Acked-by: Eelco Chaudron 
---
  lib/dpif-netdev.c | 47 ++-
  1 file changed, 42 insertions(+), 5 deletions(-)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 23cf6a6..243c1ce 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
  struct seq *reload_seq;
  uint64_t last_reload_seq;
  atomic_bool reload; /* Do we need to reload ports? */
+atomic_bool wait_for_reload;/* Can we busy wait for the next reload? */
  atomic_bool exit;   /* For terminating the pmd thread. */
  pthread_t thread;
  unsigned core_id;   /* CPU core id of this pmd thread. */
@@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
  HMAP_FOR_EACH_SAFE (poll, poll_next, node, >poll_list) {
  if (poll->rxq->pmd != pmd) {
  dp_netdev_del_rxq_from_pmd(pmd, poll);


I'm a little confused by the block below.


+
+/* This pmd might sleep after this step reload if it has no
+ * rxq remaining. Can we tell it to busy wait for new rxq at
+ * Step 6 ? */


So whats the typical cases we target here, I would think this would 
occur if PMDs have been isolated and there are no non isolated queues 
available for the rxq to be assigned to?



+if (hmap_count(>poll_list) == 0) {
+HMAP_FOR_EACH (port, node, >ports) {
+int qid;
+
+if (!netdev_is_pmd(port->netdev)) {
+continue;
+}
+
+for (qid = 0; qid < port->n_rxq; qid++) {
+struct dp_netdev_rxq *q = >rxqs[qid];
+
+if (q->pmd == pmd) {
+atomic_store_relaxed(>pmd->wait_for_reload,
+ true);


I was a little confused here, are we marking wait_for_reload true here 
so that reload in step 6 will handle any new assignment? Does this not 
put it in the busy-wait state already here in step 5? It's just from 
reading the comment it looked like busy wait status was expected in step 
6 rather than here.


Ian

+break;
+}
+}
+
+if (qid != port->n_rxq) {
+break;
+}
+}
+}
  }
  }
  ovs_mutex_unlock(>port_mutex);
@@ -5413,7 +5441,9 @@ pmd_thread_main(void *f_)
  struct pmd_perf_stats *s = >perf_stats;
  unsigned int lc = 0;
  struct polled_queue *poll_list;
+bool wait_for_reload = false;
  bool exiting;
+bool reload;
  int poll_cnt;
  int i;
  int process_packets = 0;
@@ -5441,9 +5471,16 @@ reload:
  }
  
  if (!poll_cnt) {

-while (seq_read(pmd->reload_seq) == pmd->last_reload_seq) {
-seq_wait(pmd->reload_seq, pmd->last_reload_seq);
-poll_block();
+/* Don't sleep, control thread will ask for a reload shortly. */
+if (wait_for_reload) {
+do {
+atomic_read_relaxed(>reload, );
+} while (!reload);
+} else {
+while (seq_read(pmd->reload_seq) == pmd->last_reload_seq) {
+seq_wait(pmd->reload_seq, pmd->last_reload_seq);
+poll_block();
+}
  }
  lc = UINT_MAX;
  }
@@ -5482,8 +5519,6 @@ reload:
  }
  
  if (lc++ > 1024) {

-bool reload;
-
  lc = 0;
  
  coverage_try_clear();

@@ -5503,6 +5538,7 @@ reload:
  ovs_mutex_unlock(>perf_stats.stats_mutex);
  
  poll_cnt = pmd_load_queues_and_ports(pmd, _list);

+atomic_read_relaxed(>wait_for_reload, _for_reload);
  atomic_read_relaxed(>exit, );
  /* Signal here to make sure the pmd finishes
   * reloading the updated configuration. */
@@ -5839,6 +5875,7 @@ dp_netdev_pmd_reload_done(struct dp_netdev_pmd_thread 
*pmd)
  {
  uint32_t old;
  
+atomic_store_relaxed(>wait_for_reload, false);

  atomic_store_relaxed(>reload, false);
  pmd->last_reload_seq = seq_read(pmd->reload_seq);
  atomic_sub_explicit(>dp->reloading_pmds, 1, ,



___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

[ovs-dev] [PATCH 3/5] dpif-netdev: Do not sleep when swapping queues.

[David Marchand]

When swapping queues from a pmd thread to another (q0 polled by pmd0/q1
polled by pmd1 -> q1 polled by pmd0/q0 polled by pmd1), the current
"Step 5" puts both pmds to sleep waiting for the control thread to wake
them up later.

Prefer to make them spin in such a case to avoid sleeping an
undeterministic amount of time.

Signed-off-by: David Marchand 
Acked-by: Eelco Chaudron 
---
 lib/dpif-netdev.c | 47 ++-
 1 file changed, 42 insertions(+), 5 deletions(-)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 23cf6a6..243c1ce 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -683,6 +683,7 @@ struct dp_netdev_pmd_thread {
 struct seq *reload_seq;
 uint64_t last_reload_seq;
 atomic_bool reload; /* Do we need to reload ports? */
+atomic_bool wait_for_reload;/* Can we busy wait for the next reload? */
 atomic_bool exit;   /* For terminating the pmd thread. */
 pthread_t thread;
 unsigned core_id;   /* CPU core id of this pmd thread. */
@@ -4896,6 +4897,33 @@ reconfigure_datapath(struct dp_netdev *dp)
 HMAP_FOR_EACH_SAFE (poll, poll_next, node, >poll_list) {
 if (poll->rxq->pmd != pmd) {
 dp_netdev_del_rxq_from_pmd(pmd, poll);
+
+/* This pmd might sleep after this step reload if it has no
+ * rxq remaining. Can we tell it to busy wait for new rxq at
+ * Step 6 ? */
+if (hmap_count(>poll_list) == 0) {
+HMAP_FOR_EACH (port, node, >ports) {
+int qid;
+
+if (!netdev_is_pmd(port->netdev)) {
+continue;
+}
+
+for (qid = 0; qid < port->n_rxq; qid++) {
+struct dp_netdev_rxq *q = >rxqs[qid];
+
+if (q->pmd == pmd) {
+atomic_store_relaxed(>pmd->wait_for_reload,
+ true);
+break;
+}
+}
+
+if (qid != port->n_rxq) {
+break;
+}
+}
+}
 }
 }
 ovs_mutex_unlock(>port_mutex);
@@ -5413,7 +5441,9 @@ pmd_thread_main(void *f_)
 struct pmd_perf_stats *s = >perf_stats;
 unsigned int lc = 0;
 struct polled_queue *poll_list;
+bool wait_for_reload = false;
 bool exiting;
+bool reload;
 int poll_cnt;
 int i;
 int process_packets = 0;
@@ -5441,9 +5471,16 @@ reload:
 }
 
 if (!poll_cnt) {
-while (seq_read(pmd->reload_seq) == pmd->last_reload_seq) {
-seq_wait(pmd->reload_seq, pmd->last_reload_seq);
-poll_block();
+/* Don't sleep, control thread will ask for a reload shortly. */
+if (wait_for_reload) {
+do {
+atomic_read_relaxed(>reload, );
+} while (!reload);
+} else {
+while (seq_read(pmd->reload_seq) == pmd->last_reload_seq) {
+seq_wait(pmd->reload_seq, pmd->last_reload_seq);
+poll_block();
+}
 }
 lc = UINT_MAX;
 }
@@ -5482,8 +5519,6 @@ reload:
 }
 
 if (lc++ > 1024) {
-bool reload;
-
 lc = 0;
 
 coverage_try_clear();
@@ -5503,6 +5538,7 @@ reload:
 ovs_mutex_unlock(>perf_stats.stats_mutex);
 
 poll_cnt = pmd_load_queues_and_ports(pmd, _list);
+atomic_read_relaxed(>wait_for_reload, _for_reload);
 atomic_read_relaxed(>exit, );
 /* Signal here to make sure the pmd finishes
  * reloading the updated configuration. */
@@ -5839,6 +5875,7 @@ dp_netdev_pmd_reload_done(struct dp_netdev_pmd_thread 
*pmd)
 {
 uint32_t old;
 
+atomic_store_relaxed(>wait_for_reload, false);
 atomic_store_relaxed(>reload, false);
 pmd->last_reload_seq = seq_read(pmd->reload_seq);
 atomic_sub_explicit(>dp->reloading_pmds, 1, ,
-- 
1.8.3.1

___
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev