[dpdk-dev] eventdev: fix incorrect MP/MC tail updates in rte_event_ring
Checks
Commit Message
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(-)
Comments
> 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
-----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.
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
@@ -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)