eventdev: avoid non-burst shortcut for variable-size bursts
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Commit Message
Use non-burst event enqueue and dequeue calls from burst enqueue and
dequeue only when the burst size is compile-time constant (and equal
to one).
Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
lib/eventdev/rte_eventdev.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Comments
> From: Mattias Rönnblom [mailto:mattias.ronnblom@ericsson.com]
> Sent: Thursday, 11 May 2023 08.43
>
> Use non-burst event enqueue and dequeue calls from burst enqueue and
> dequeue only when the burst size is compile-time constant (and equal
> to one).
>
> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> ---
> lib/eventdev/rte_eventdev.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
> index a90e23ac8b..8af15816db 100644
> --- a/lib/eventdev/rte_eventdev.h
> +++ b/lib/eventdev/rte_eventdev.h
> @@ -1944,7 +1944,7 @@ __rte_event_enqueue_burst(uint8_t dev_id, uint8_t
> port_id,
> * Allow zero cost non burst mode routine invocation if application
> * requests nb_events as const one
> */
> - if (nb_events == 1)
> + if (__builtin_constant_p(nb_events) && nb_events == 1)
In my experience using __builtin_constant_p(), you need __extension__(__builtin_constant_p(nb_events)) to avoid warnings about using this non-standard feature.
> return (fp_ops->enqueue)(port, ev);
> else
> return fn(port, ev, nb_events);
> @@ -2200,7 +2200,7 @@ rte_event_dequeue_burst(uint8_t dev_id, uint8_t port_id,
> struct rte_event ev[],
> * Allow zero cost non burst mode routine invocation if application
> * requests nb_events as const one
> */
> - if (nb_events == 1)
> + if (__builtin_constant_p(nb_events) && nb_events == 1)
> return (fp_ops->dequeue)(port, ev, timeout_ticks);
> else
> return (fp_ops->dequeue_burst)(port, ev, nb_events,
> --
> 2.34.1
With __extension__() added,
Acked-by: Morten Brørup <mb@smartsharesystems.com>
On 2023-05-11 09:09, Morten Brørup wrote:
>> From: Mattias Rönnblom [mailto:mattias.ronnblom@ericsson.com]
>> Sent: Thursday, 11 May 2023 08.43
>>
>> Use non-burst event enqueue and dequeue calls from burst enqueue and
>> dequeue only when the burst size is compile-time constant (and equal
>> to one).
>>
>> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
>> ---
>> lib/eventdev/rte_eventdev.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
>> index a90e23ac8b..8af15816db 100644
>> --- a/lib/eventdev/rte_eventdev.h
>> +++ b/lib/eventdev/rte_eventdev.h
>> @@ -1944,7 +1944,7 @@ __rte_event_enqueue_burst(uint8_t dev_id, uint8_t
>> port_id,
>> * Allow zero cost non burst mode routine invocation if application
>> * requests nb_events as const one
>> */
>> - if (nb_events == 1)
>> + if (__builtin_constant_p(nb_events) && nb_events == 1)
>
> In my experience using __builtin_constant_p(), you need __extension__(__builtin_constant_p(nb_events)) to avoid warnings about using this non-standard feature.
>
Yes, since it's a public header. Thanks.
>> return (fp_ops->enqueue)(port, ev);
>> else
>> return fn(port, ev, nb_events);
>> @@ -2200,7 +2200,7 @@ rte_event_dequeue_burst(uint8_t dev_id, uint8_t port_id,
>> struct rte_event ev[],
>> * Allow zero cost non burst mode routine invocation if application
>> * requests nb_events as const one
>> */
>> - if (nb_events == 1)
>> + if (__builtin_constant_p(nb_events) && nb_events == 1)
>> return (fp_ops->dequeue)(port, ev, timeout_ticks);
>> else
>> return (fp_ops->dequeue_burst)(port, ev, nb_events,
>> --
>> 2.34.1
>
> With __extension__() added,
>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
>
> From: Mattias Rönnblom [mailto:mattias.ronnblom@ericsson.com]
> Sent: Thursday, 11 May 2023 10.30
>
> On 2023-05-11 09:09, Morten Brørup wrote:
[...]
> > In my experience using __builtin_constant_p(), you need
> __extension__(__builtin_constant_p(nb_events)) to avoid warnings about using
> this non-standard feature.
> >
>
> Yes, since it's a public header. Thanks.
If you run meson with -Dcheck_includes=true, ninja will catch it.
Unfortunately, the build time increases significantly when using this option.
@@ -1944,7 +1944,7 @@ __rte_event_enqueue_burst(uint8_t dev_id, uint8_t port_id,
* Allow zero cost non burst mode routine invocation if application
* requests nb_events as const one
*/
- if (nb_events == 1)
+ if (__builtin_constant_p(nb_events) && nb_events == 1)
return (fp_ops->enqueue)(port, ev);
else
return fn(port, ev, nb_events);
@@ -2200,7 +2200,7 @@ rte_event_dequeue_burst(uint8_t dev_id, uint8_t port_id, struct rte_event ev[],
* Allow zero cost non burst mode routine invocation if application
* requests nb_events as const one
*/
- if (nb_events == 1)
+ if (__builtin_constant_p(nb_events) && nb_events == 1)
return (fp_ops->dequeue)(port, ev, timeout_ticks);
else
return (fp_ops->dequeue_burst)(port, ev, nb_events,