* [dpdk-dev] [PATCH] event/sw: add unlikely branch predict
@ 2018-02-27 20:08 Vipin Varghese
2018-03-14 13:06 ` Laatz, Kevin
0 siblings, 1 reply; 3+ messages in thread
From: Vipin Varghese @ 2018-02-27 20:08 UTC (permalink / raw)
To: dev, harry.van.haaren; +Cc: Vipin Varghese
For most run cases 'sw->started' holds true. Adding a branch prediction
suggestion to compiler helps as this is first conditional check just
after entering the function.
Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
---
drivers/event/sw/sw_evdev_scheduler.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/event/sw/sw_evdev_scheduler.c b/drivers/event/sw/sw_evdev_scheduler.c
index 3106eb3..17bd4c0 100644
--- a/drivers/event/sw/sw_evdev_scheduler.c
+++ b/drivers/event/sw/sw_evdev_scheduler.c
@@ -508,7 +508,7 @@ sw_event_schedule(struct rte_eventdev *dev)
uint32_t i;
sw->sched_called++;
- if (!sw->started)
+ if (unlikely(!sw->started))
return;
do {
--
2.7.4
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dpdk-dev] [PATCH] event/sw: add unlikely branch predict
2018-02-27 20:08 [dpdk-dev] [PATCH] event/sw: add unlikely branch predict Vipin Varghese
@ 2018-03-14 13:06 ` Laatz, Kevin
2018-03-20 5:39 ` Jerin Jacob
0 siblings, 1 reply; 3+ messages in thread
From: Laatz, Kevin @ 2018-03-14 13:06 UTC (permalink / raw)
To: Vipin Varghese; +Cc: dev, harry.van.haaren
On 27/02/2018 20:08, Vipin Varghese wrote:
> For most run cases 'sw->started' holds true. Adding a branch prediction
> suggestion to compiler helps as this is first conditional check just
> after entering the function.
>
> Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
> ---
> drivers/event/sw/sw_evdev_scheduler.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/event/sw/sw_evdev_scheduler.c b/drivers/event/sw/sw_evdev_scheduler.c
> index 3106eb3..17bd4c0 100644
> --- a/drivers/event/sw/sw_evdev_scheduler.c
> +++ b/drivers/event/sw/sw_evdev_scheduler.c
> @@ -508,7 +508,7 @@ sw_event_schedule(struct rte_eventdev *dev)
> uint32_t i;
>
> sw->sched_called++;
> - if (!sw->started)
> + if (unlikely(!sw->started))
> return;
>
> do {
Acked-by: Kevin Laatz <kevin.laatz@intel.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dpdk-dev] [PATCH] event/sw: add unlikely branch predict
2018-03-14 13:06 ` Laatz, Kevin
@ 2018-03-20 5:39 ` Jerin Jacob
0 siblings, 0 replies; 3+ messages in thread
From: Jerin Jacob @ 2018-03-20 5:39 UTC (permalink / raw)
To: Laatz, Kevin; +Cc: Vipin Varghese, dev, harry.van.haaren
-----Original Message-----
> Date: Wed, 14 Mar 2018 13:06:35 +0000
> From: "Laatz, Kevin" <kevin.laatz@intel.com>
> To: Vipin Varghese <vipin.varghese@intel.com>
> CC: dev@dpdk.org, harry.van.haaren@intel.com
> Subject: Re: [dpdk-dev] [PATCH] event/sw: add unlikely branch predict
> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
> Thunderbird/52.6.0
>
>
> On 27/02/2018 20:08, Vipin Varghese wrote:
> > For most run cases 'sw->started' holds true. Adding a branch prediction
> > suggestion to compiler helps as this is first conditional check just
> > after entering the function.
> >
> > Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
> > ---
> > drivers/event/sw/sw_evdev_scheduler.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/event/sw/sw_evdev_scheduler.c b/drivers/event/sw/sw_evdev_scheduler.c
> > index 3106eb3..17bd4c0 100644
> > --- a/drivers/event/sw/sw_evdev_scheduler.c
> > +++ b/drivers/event/sw/sw_evdev_scheduler.c
> > @@ -508,7 +508,7 @@ sw_event_schedule(struct rte_eventdev *dev)
> > uint32_t i;
> > sw->sched_called++;
> > - if (!sw->started)
> > + if (unlikely(!sw->started))
> > return;
> > do {
>
> Acked-by: Kevin Laatz <kevin.laatz@intel.com>
Applied to dpdk-next-eventdev/master. Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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