[dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Mattias Rönnblom]

rte_event_ring enqueue and dequeue tail updates were hardcoded for a
SC/SP configuration.

Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>
---
 lib/librte_eventdev/rte_event_ring.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_ring.h b/lib/librte_eventdev/rte_event_ring.h
index 29d4228..07b4559 100644
--- a/lib/librte_eventdev/rte_event_ring.h
+++ b/lib/librte_eventdev/rte_event_ring.h
@@ -99,7 +99,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
 
 	ENQUEUE_PTRS(&r->r, &r[1], prod_head, events, n, struct rte_event);
 
-	update_tail(&r->r.prod, prod_head, prod_next, 1, 1);
+	update_tail(&r->r.prod, prod_head, prod_next, 1, r->r.prod.single);
 end:
 	if (free_space != NULL)
 		*free_space = free_entries - n;
@@ -140,7 +140,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
 
 	DEQUEUE_PTRS(&r->r, &r[1], cons_head, events, n, struct rte_event);
 
-	update_tail(&r->r.cons, cons_head, cons_next, 1, 0);
+	update_tail(&r->r.cons, cons_head, cons_next, 1, r->r.cons.single);
 
 end:
 	if (available != NULL)
-- 
2.7.4

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Van Haaren, Harry]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mattias Rönnblom
> Sent: Wednesday, March 28, 2018 10:17 AM
> To: dev@dpdk.org
> Cc: Mattias Rönnblom <hofors@lysator.liu.se>
> Subject: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in
> rte_event_ring
> 
> rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> SC/SP configuration.
> 
> Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>
> ---

Hi Mattias,


Thanks for your patch, a few notes;

1)
You can CC the maintainer of a section - the event rings falls under
the eventdev library, and Jerin Jacob is the maintainer.


2)
In DPDK we note patches that are "Fixes",
so we can track what commit they fix. Fixes patches are
also often candidates for backporting.

Details on getting the fixes line here:
https://dpdk.org/doc/guides/contributing/patches.html#commit-messages-body

For this patch, the following is the fixline:

Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
Cc: bruce.richardson@intel.com


>  lib/librte_eventdev/rte_event_ring.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eventdev/rte_event_ring.h
> b/lib/librte_eventdev/rte_event_ring.h
> index 29d4228..07b4559 100644
> --- a/lib/librte_eventdev/rte_event_ring.h
> +++ b/lib/librte_eventdev/rte_event_ring.h
> @@ -99,7 +99,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
> 
>  	ENQUEUE_PTRS(&r->r, &r[1], prod_head, events, n, struct rte_event);
> 
> -	update_tail(&r->r.prod, prod_head, prod_next, 1, 1);
> +	update_tail(&r->r.prod, prod_head, prod_next, 1, r->r.prod.single);
>  end:
>  	if (free_space != NULL)
>  		*free_space = free_entries - n;
> @@ -140,7 +140,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
> 
>  	DEQUEUE_PTRS(&r->r, &r[1], cons_head, events, n, struct rte_event);
> 
> -	update_tail(&r->r.cons, cons_head, cons_next, 1, 0);
> +	update_tail(&r->r.cons, cons_head, cons_next, 1, r->r.cons.single);


The signature of update_tail() is as follows:

static __rte_always_inline void
update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,
		uint32_t single, uint32_t enqueue)

It seems to be that the 2nd last parameter sets the single/multi producer?

The value that has been changed in this patch is the enqueue or dequeue parameter, which changes the type of memory barrier that is used..


Please review this code, and you can post a V2 of the patch in reply to this one (see contrib guidelines above for details).


Regards, -Harry

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Jerin Jacob]

-----Original Message-----
> Date: Thu, 29 Mar 2018 12:38:01 +0000
> From: "Van Haaren, Harry" <harry.van.haaren@intel.com>
> To: Mattias Rönnblom <hofors@lysator.liu.se>, "dev@dpdk.org" <dev@dpdk.org>
> Subject: Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates
>  in	rte_event_ring
> 
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mattias Rönnblom
> > Sent: Wednesday, March 28, 2018 10:17 AM
> > To: dev@dpdk.org
> > Cc: Mattias Rönnblom <hofors@lysator.liu.se>
> > Subject: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in
> > rte_event_ring
> > 
> > rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> > SC/SP configuration.
> > 
> > Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>
> > ---
> 
> Hi Mattias,
> 
> 
> Thanks for your patch, a few notes;
> 
> 1)
> You can CC the maintainer of a section - the event rings falls under
> the eventdev library, and Jerin Jacob is the maintainer.
> 
> 
> 2)
> In DPDK we note patches that are "Fixes",
> so we can track what commit they fix. Fixes patches are
> also often candidates for backporting.
> 
> Details on getting the fixes line here:
> https://dpdk.org/doc/guides/contributing/patches.html#commit-messages-body
> 
> For this patch, the following is the fixline:
> 
> Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> Cc: bruce.richardson@intel.com
> 

Hi Mattias,

Could you please the v2 version addressing Harry's comments.

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Mattias Rönnblom]

On 2018-03-29 14:38, Van Haaren, Harry wrote:
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mattias Rönnblom
>> Sent: Wednesday, March 28, 2018 10:17 AM
>> To: dev@dpdk.org
>> Cc: Mattias Rönnblom <hofors@lysator.liu.se>
>> Subject: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in
>> rte_event_ring
>>
>> rte_event_ring enqueue and dequeue tail updates were hardcoded for a
>> SC/SP configuration.
>>
>> Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>
>> ---
> 
> Hi Mattias,
> 
> 
> Thanks for your patch, a few notes;
> 
> 1)
> You can CC the maintainer of a section - the event rings falls under
> the eventdev library, and Jerin Jacob is the maintainer.
> 
> 
> 2)
> In DPDK we note patches that are "Fixes",
> so we can track what commit they fix. Fixes patches are
> also often candidates for backporting.
> 
> Details on getting the fixes line here:
> https://dpdk.org/doc/guides/contributing/patches.html#commit-messages-body
> 
> For this patch, the following is the fixline:
> 
> Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> Cc: bruce.richardson@intel.com
> 
> 

Thanks for your help. I'll resubmit and try to get the administrative 
details correct.

>>   lib/librte_eventdev/rte_event_ring.h | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_eventdev/rte_event_ring.h
>> b/lib/librte_eventdev/rte_event_ring.h
>> index 29d4228..07b4559 100644
>> --- a/lib/librte_eventdev/rte_event_ring.h
>> +++ b/lib/librte_eventdev/rte_event_ring.h
>> @@ -99,7 +99,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
>>
>>   	ENQUEUE_PTRS(&r->r, &r[1], prod_head, events, n, struct rte_event);
>>
>> -	update_tail(&r->r.prod, prod_head, prod_next, 1, 1);
>> +	update_tail(&r->r.prod, prod_head, prod_next, 1, r->r.prod.single);
>>   end:
>>   	if (free_space != NULL)
>>   		*free_space = free_entries - n;
>> @@ -140,7 +140,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
>>
>>   	DEQUEUE_PTRS(&r->r, &r[1], cons_head, events, n, struct rte_event);
>>
>> -	update_tail(&r->r.cons, cons_head, cons_next, 1, 0);
>> +	update_tail(&r->r.cons, cons_head, cons_next, 1, r->r.cons.single);
> 
> 
> The signature of update_tail() is as follows:
> 
> static __rte_always_inline void
> update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,
> 		uint32_t single, uint32_t enqueue)
> 
> It seems to be that the 2nd last parameter sets the single/multi producer?
> 

Yes, you are right. I ported this fix from my 17.08 tree, and 
update_tail() has changed since then - something I failed to notice.

I reproduced the issue on 17.08, and even on a machine with a strong 
memory model, the event ring doesn't work correctly in a MP/SC 
configuration. With the fix, it at least passes my tests on 17.08. I 
didn't try MP/MC, and I also didn't try anything beyond building on HEAD.

Regards,
	Mattias

[dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Mattias Rönnblom]

rte_event_ring enqueue and dequeue tail updates were hardcoded for a
SC/SP configuration.

Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
Cc: bruce.richardson@intel.com

Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>

v2:
* Fixed issue with update_tail() parameter order.
---
 lib/librte_eventdev/rte_event_ring.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_ring.h b/lib/librte_eventdev/rte_event_ring.h
index 29d4228..827a320 100644
--- a/lib/librte_eventdev/rte_event_ring.h
+++ b/lib/librte_eventdev/rte_event_ring.h
@@ -99,7 +99,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
 
 	ENQUEUE_PTRS(&r->r, &r[1], prod_head, events, n, struct rte_event);
 
-	update_tail(&r->r.prod, prod_head, prod_next, 1, 1);
+	update_tail(&r->r.prod, prod_head, prod_next, r->r.prod.single, 1);
 end:
 	if (free_space != NULL)
 		*free_space = free_entries - n;
@@ -140,7 +140,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
 
 	DEQUEUE_PTRS(&r->r, &r[1], cons_head, events, n, struct rte_event);
 
-	update_tail(&r->r.cons, cons_head, cons_next, 1, 0);
+	update_tail(&r->r.cons, cons_head, cons_next, r->r.cons.single, 0);
 
 end:
 	if (available != NULL)
-- 
2.7.4

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Jerin Jacob]

-----Original Message-----
> Date: Tue, 3 Apr 2018 10:19:03 +0200
> From: Mattias Rönnblom <hofors@lysator.liu.se>
> To: dev@dpdk.org
> CC: jerin.jacob@caviumnetworks.com, Mattias Rönnblom
>  <hofors@lysator.liu.se>, bruce.richardson@intel.com
> Subject: [PATCH] eventdev: fix incorrect MP/MC tail updates in
>  rte_event_ring
> X-Mailer: git-send-email 2.7.4
> 
> rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> SC/SP configuration.
> 
> Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> Cc: bruce.richardson@intel.com

Bruce,

As an original author of this file, Can you review this change?

> 
> Signed-off-by: Mattias Rönnblom <hofors@lysator.liu.se>
> 
> v2:
> * Fixed issue with update_tail() parameter order.
> ---
>  lib/librte_eventdev/rte_event_ring.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eventdev/rte_event_ring.h b/lib/librte_eventdev/rte_event_ring.h
> index 29d4228..827a320 100644
> --- a/lib/librte_eventdev/rte_event_ring.h
> +++ b/lib/librte_eventdev/rte_event_ring.h
> @@ -99,7 +99,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
>  
>  	ENQUEUE_PTRS(&r->r, &r[1], prod_head, events, n, struct rte_event);
>  
> -	update_tail(&r->r.prod, prod_head, prod_next, 1, 1);
> +	update_tail(&r->r.prod, prod_head, prod_next, r->r.prod.single, 1);
>  end:
>  	if (free_space != NULL)
>  		*free_space = free_entries - n;
> @@ -140,7 +140,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
>  
>  	DEQUEUE_PTRS(&r->r, &r[1], cons_head, events, n, struct rte_event);
>  
> -	update_tail(&r->r.cons, cons_head, cons_next, 1, 0);
> +	update_tail(&r->r.cons, cons_head, cons_next, r->r.cons.single, 0);
>  
>  end:
>  	if (available != NULL)
> -- 
> 2.7.4
> 

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Bruce Richardson]

On Wed, Apr 04, 2018 at 06:22:26AM +0530, Jerin Jacob wrote:
> -----Original Message-----
> > Date: Tue, 3 Apr 2018 10:19:03 +0200
> > From: Mattias Rönnblom <hofors@lysator.liu.se>
> > To: dev@dpdk.org
> > CC: jerin.jacob@caviumnetworks.com, Mattias Rönnblom
> >  <hofors@lysator.liu.se>, bruce.richardson@intel.com
> > Subject: [PATCH] eventdev: fix incorrect MP/MC tail updates in
> >  rte_event_ring
> > X-Mailer: git-send-email 2.7.4
> > 
> > rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> > SC/SP configuration.
> > 
> > Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> > Cc: bruce.richardson@intel.com
> 
> Bruce,
> 
> As an original author of this file, Can you review this change?
> 

Yes, LTGM

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Jerin Jacob]

-----Original Message-----
> Date: Wed, 4 Apr 2018 09:52:18 +0100
> From: Bruce Richardson <bruce.richardson@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> CC: Mattias Rönnblom <hofors@lysator.liu.se>, dev@dpdk.org
> Subject: Re: [PATCH] eventdev: fix incorrect MP/MC tail updates in
>  rte_event_ring
> User-Agent: Mutt/1.9.4 (2018-02-28)
> 
> On Wed, Apr 04, 2018 at 06:22:26AM +0530, Jerin Jacob wrote:
> > -----Original Message-----
> > > Date: Tue, 3 Apr 2018 10:19:03 +0200
> > > From: Mattias Rönnblom <hofors@lysator.liu.se>
> > > To: dev@dpdk.org
> > > CC: jerin.jacob@caviumnetworks.com, Mattias Rönnblom
> > >  <hofors@lysator.liu.se>, bruce.richardson@intel.com
> > > Subject: [PATCH] eventdev: fix incorrect MP/MC tail updates in
> > >  rte_event_ring
> > > X-Mailer: git-send-email 2.7.4
> > > 
> > > rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> > > SC/SP configuration.
> > > 
> > > Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> > > Cc: bruce.richardson@intel.com
> > 
> > Bruce,
> > 
> > As an original author of this file, Can you review this change?
> > 
> 
> Yes, LTGM
> 
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Cc: stable@dpdk.org

Applied to dpdk-next-eventdev/master. Thanks.

> 

Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in rte_event_ring

[Van Haaren, Harry]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson
> Sent: Wednesday, April 4, 2018 9:52 AM
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> Cc: Mattias Rönnblom <hofors@lysator.liu.se>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] eventdev: fix incorrect MP/MC tail updates in
> rte_event_ring
> 
> On Wed, Apr 04, 2018 at 06:22:26AM +0530, Jerin Jacob wrote:
> > -----Original Message-----
> > > Date: Tue, 3 Apr 2018 10:19:03 +0200
> > > From: Mattias Rönnblom <hofors@lysator.liu.se>
> > > To: dev@dpdk.org
> > > CC: jerin.jacob@caviumnetworks.com, Mattias Rönnblom
> > >  <hofors@lysator.liu.se>, bruce.richardson@intel.com
> > > Subject: [PATCH] eventdev: fix incorrect MP/MC tail updates in
> > >  rte_event_ring
> > > X-Mailer: git-send-email 2.7.4
> > >
> > > rte_event_ring enqueue and dequeue tail updates were hardcoded for a
> > > SC/SP configuration.
> > >
> > > Fixes: dc39e2f359b5 ("eventdev: add ring structure for events")
> > > Cc: bruce.richardson@intel.com

Hi Mattias,

I think this is a v2 of the patch here:
http://dpdk.org/dev/patchwork/patch/36604/

When doing the git-send-email, we should pass the -v2 parameter, so the subject says [PATCH v2].
It is helpful to CC the people who replied to the V1 of the patch, so they are aware of the re-submit.

Bruce has Acked this patch, so it can be merged now - above is just for future reference.

Regards, -Harry

<snip>