[v7,1/2] ring: add reset API to flush the ring when not in use

Message ID 1552620686-10347-2-git-send-email-gavin.hu@arm.com
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show
Series
  • new ring reset api and use it by hash
Related show

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Context Check Description
ci/intel-Performance-Testing success Performance Testing PASS
ci/mellanox-Performance-Testing success Performance Testing PASS
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Gavin Hu (Arm Technology China) March 15, 2019, 3:31 a.m.
Currently, the flush is done by dequeuing the ring in a while loop. It is
much simpler to flush the queue by resetting the head and tail indices.

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org

Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
---
 lib/librte_ring/rte_ring.h           | 20 ++++++++++++++++++++
 lib/librte_ring/rte_ring_version.map |  7 +++++++
 2 files changed, 27 insertions(+)

Comments

Olivier Matz March 29, 2019, 2:17 p.m. | #1
Hi,

On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> Currently, the flush is done by dequeuing the ring in a while loop. It is
> much simpler to flush the queue by resetting the head and tail indices.
> 
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> ---
>  lib/librte_ring/rte_ring.h           | 20 ++++++++++++++++++++
>  lib/librte_ring/rte_ring_version.map |  7 +++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
> index af5444a..2830300 100644
> --- a/lib/librte_ring/rte_ring.h
> +++ b/lib/librte_ring/rte_ring.h
> @@ -671,6 +671,26 @@ rte_ring_dequeue(struct rte_ring *r, void **obj_p)
>  }
>  
>  /**
> + * Flush a ring.
> + *
> + * This function flush all the elements in a ring
> + *
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * @warning
> + * Make sure the ring is not in use while calling this function.
> + *
> + * @param r
> + *   A pointer to the ring structure.
> + */
> +static inline void __rte_experimental
> +rte_ring_reset(struct rte_ring *r)
> +{
> +	r->prod.head = r->cons.head = 0;
> +	r->prod.tail = r->cons.tail = 0;
> +}
> +
> +/**
>   * Return the number of entries in a ring.
>   *
>   * @param r
> diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
> index d935efd..581d9ca 100644
> --- a/lib/librte_ring/rte_ring_version.map
> +++ b/lib/librte_ring/rte_ring_version.map
> @@ -17,3 +17,10 @@ DPDK_2.2 {
>  	rte_ring_free;
>  
>  } DPDK_2.0;
> +
> +EXPERIMENTAL {
> +    global:
> +
> +	rte_ring_reset;
> +
> +};
> -- 
> 2.7.4
> 

To me, a static inline function does not need to be added in
rte_ring_version.map (or is it due to a check script checking the
__rte_experimental tag ?). I found at least one commit where it
is not the case:
c277b34c1b3b ("mbuf: add function returning buffer address")

There are 2 options:
1- remove the rte_ring_version.map part of the patch.
2- change the static inline function into a standard function.

I would prefer 2-, because it allows to keep an api/abi compat
layer in the future.

Regards
Olivier
Thomas Monjalon July 4, 2019, 2:42 p.m. | #2
29/03/2019 15:17, Olivier Matz:
> Hi,
> 
> On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > much simpler to flush the queue by resetting the head and tail indices.
> > 
> > Fixes: af75078fece3 ("first public release")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > ---
> > --- a/lib/librte_ring/rte_ring_version.map
> > +++ b/lib/librte_ring/rte_ring_version.map
> > @@ -17,3 +17,10 @@ DPDK_2.2 {
> >  	rte_ring_free;
> >  
> >  } DPDK_2.0;
> > +
> > +EXPERIMENTAL {
> > +    global:
> > +
> > +	rte_ring_reset;
> > +
> > +};
> 
> To me, a static inline function does not need to be added in
> rte_ring_version.map (or is it due to a check script checking the
> __rte_experimental tag ?). I found at least one commit where it
> is not the case:
> c277b34c1b3b ("mbuf: add function returning buffer address")
> 
> There are 2 options:
> 1- remove the rte_ring_version.map part of the patch.
> 2- change the static inline function into a standard function.
> 
> I would prefer 2-, because it allows to keep an api/abi compat
> layer in the future.

There are no news about this patch.
I classify it as changes requested.
Gavin Hu (Arm Technology China) July 12, 2019, 9:32 a.m. | #3
Hi Olivier and Thomas,

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Thursday, July 4, 2019 10:42 PM
> To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> Cc: dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>; nd
> <nd@arm.com>; jerinj@marvell.com; hemant.agrawal@nxp.com;
> Nipun.gupta@nxp.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; i.maximets@samsung.com;
> stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> when not in use
> 
> 29/03/2019 15:17, Olivier Matz:
> > Hi,
> >
> > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > > much simpler to flush the queue by resetting the head and tail indices.
> > >
> > > Fixes: af75078fece3 ("first public release")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > > ---
> > > --- a/lib/librte_ring/rte_ring_version.map
> > > +++ b/lib/librte_ring/rte_ring_version.map
> > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > >  	rte_ring_free;
> > >
> > >  } DPDK_2.0;
> > > +
> > > +EXPERIMENTAL {
> > > +    global:
> > > +
> > > +	rte_ring_reset;
> > > +
> > > +};
> >
> > To me, a static inline function does not need to be added in
> > rte_ring_version.map (or is it due to a check script checking the
> > __rte_experimental tag ?). I found at least one commit where it
> > is not the case:
> > c277b34c1b3b ("mbuf: add function returning buffer address")
> >
> > There are 2 options:
> > 1- remove the rte_ring_version.map part of the patch.
> > 2- change the static inline function into a standard function.
> >
> > I would prefer 2-, because it allows to keep an api/abi compat
> > layer in the future.
> 
> There are no news about this patch.
> I classify it as changes requested.
> 
Sorry for missed your comments for long time, I just submitted v8.
I took the first option as it is in the data path and to keep consistent to its neighboring functions.
Olivier Matz July 12, 2019, 9:53 a.m. | #4
Hi Gavin,

On Fri, Jul 12, 2019 at 09:32:39AM +0000, Gavin Hu (Arm Technology China) wrote:
> Hi Olivier and Thomas,
> 
> > -----Original Message-----
> > From: Thomas Monjalon <thomas@monjalon.net>
> > Sent: Thursday, July 4, 2019 10:42 PM
> > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > Cc: dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>; nd
> > <nd@arm.com>; jerinj@marvell.com; hemant.agrawal@nxp.com;
> > Nipun.gupta@nxp.com; Honnappa Nagarahalli
> > <Honnappa.Nagarahalli@arm.com>; i.maximets@samsung.com;
> > stable@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> > when not in use
> > 
> > 29/03/2019 15:17, Olivier Matz:
> > > Hi,
> > >
> > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > > > much simpler to flush the queue by resetting the head and tail indices.
> > > >
> > > > Fixes: af75078fece3 ("first public release")
> > > > Cc: stable@dpdk.org
> > > >
> > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > > > ---
> > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > >  	rte_ring_free;
> > > >
> > > >  } DPDK_2.0;
> > > > +
> > > > +EXPERIMENTAL {
> > > > +    global:
> > > > +
> > > > +	rte_ring_reset;
> > > > +
> > > > +};
> > >
> > > To me, a static inline function does not need to be added in
> > > rte_ring_version.map (or is it due to a check script checking the
> > > __rte_experimental tag ?). I found at least one commit where it
> > > is not the case:
> > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > >
> > > There are 2 options:
> > > 1- remove the rte_ring_version.map part of the patch.
> > > 2- change the static inline function into a standard function.
> > >
> > > I would prefer 2-, because it allows to keep an api/abi compat
> > > layer in the future.
> > 
> > There are no news about this patch.
> > I classify it as changes requested.
> > 
> Sorry for missed your comments for long time, I just submitted v8.
> I took the first option as it is in the data path and to keep consistent to its neighboring functions. 

Could you give a little more context about why you need to reset
the ring in the data path? I see that it is used in rte_hash_reset(),
but in my thinking, this was more used at init/exit.

Thanks,
Olivier
Gavin Hu (Arm Technology China) July 12, 2019, 11:06 a.m. | #5
Hi Olivier,

> -----Original Message-----
> From: Olivier Matz <olivier.matz@6wind.com>
> Sent: Friday, July 12, 2019 5:54 PM
> To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> Cc: thomas@monjalon.net; dev@dpdk.org; nd <nd@arm.com>;
> jerinj@marvell.com; hemant.agrawal@nxp.com; Nipun.gupta@nxp.com;
> Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> i.maximets@samsung.com; stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> when not in use
> 
> Hi Gavin,
> 
> On Fri, Jul 12, 2019 at 09:32:39AM +0000, Gavin Hu (Arm Technology China)
> wrote:
> > Hi Olivier and Thomas,
> >
> > > -----Original Message-----
> > > From: Thomas Monjalon <thomas@monjalon.net>
> > > Sent: Thursday, July 4, 2019 10:42 PM
> > > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > > Cc: dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>; nd
> > > <nd@arm.com>; jerinj@marvell.com; hemant.agrawal@nxp.com;
> > > Nipun.gupta@nxp.com; Honnappa Nagarahalli
> > > <Honnappa.Nagarahalli@arm.com>; i.maximets@samsung.com;
> > > stable@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> > > when not in use
> > >
> > > 29/03/2019 15:17, Olivier Matz:
> > > > Hi,
> > > >
> > > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > > > > much simpler to flush the queue by resetting the head and tail indices.
> > > > >
> > > > > Fixes: af75078fece3 ("first public release")
> > > > > Cc: stable@dpdk.org
> > > > >
> > > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > > > > ---
> > > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > > >  	rte_ring_free;
> > > > >
> > > > >  } DPDK_2.0;
> > > > > +
> > > > > +EXPERIMENTAL {
> > > > > +    global:
> > > > > +
> > > > > +	rte_ring_reset;
> > > > > +
> > > > > +};
> > > >
> > > > To me, a static inline function does not need to be added in
> > > > rte_ring_version.map (or is it due to a check script checking the
> > > > __rte_experimental tag ?). I found at least one commit where it
> > > > is not the case:
> > > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > > >
> > > > There are 2 options:
> > > > 1- remove the rte_ring_version.map part of the patch.
> > > > 2- change the static inline function into a standard function.
> > > >
> > > > I would prefer 2-, because it allows to keep an api/abi compat
> > > > layer in the future.
> > >
> > > There are no news about this patch.
> > > I classify it as changes requested.
> > >
> > Sorry for missed your comments for long time, I just submitted v8.
> > I took the first option as it is in the data path and to keep consistent to its
> neighboring functions.
> 
> Could you give a little more context about why you need to reset
> the ring in the data path? I see that it is used in rte_hash_reset(),
> but in my thinking, this was more used at init/exit.
Sorry,literally it is in the control path, but I was impressed it will impact the 
Data path performance when discussing this patch with Honnappa. 
> 
> Thanks,
> Olivier
Olivier Matz July 12, 2019, 11:48 a.m. | #6
Hi Gavin,

On Fri, Jul 12, 2019 at 11:06:28AM +0000, Gavin Hu (Arm Technology China) wrote:
> Hi Olivier,
> 
> > -----Original Message-----
> > From: Olivier Matz <olivier.matz@6wind.com>
> > Sent: Friday, July 12, 2019 5:54 PM
> > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > Cc: thomas@monjalon.net; dev@dpdk.org; nd <nd@arm.com>;
> > jerinj@marvell.com; hemant.agrawal@nxp.com; Nipun.gupta@nxp.com;
> > Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> > i.maximets@samsung.com; stable@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> > when not in use
> > 
> > Hi Gavin,
> > 
> > On Fri, Jul 12, 2019 at 09:32:39AM +0000, Gavin Hu (Arm Technology China)
> > wrote:
> > > Hi Olivier and Thomas,
> > >
> > > > -----Original Message-----
> > > > From: Thomas Monjalon <thomas@monjalon.net>
> > > > Sent: Thursday, July 4, 2019 10:42 PM
> > > > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > > > Cc: dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>; nd
> > > > <nd@arm.com>; jerinj@marvell.com; hemant.agrawal@nxp.com;
> > > > Nipun.gupta@nxp.com; Honnappa Nagarahalli
> > > > <Honnappa.Nagarahalli@arm.com>; i.maximets@samsung.com;
> > > > stable@dpdk.org
> > > > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> > > > when not in use
> > > >
> > > > 29/03/2019 15:17, Olivier Matz:
> > > > > Hi,
> > > > >
> > > > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > > > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > > > > > much simpler to flush the queue by resetting the head and tail indices.
> > > > > >
> > > > > > Fixes: af75078fece3 ("first public release")
> > > > > > Cc: stable@dpdk.org
> > > > > >
> > > > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > > > > > ---
> > > > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > > > >  	rte_ring_free;
> > > > > >
> > > > > >  } DPDK_2.0;
> > > > > > +
> > > > > > +EXPERIMENTAL {
> > > > > > +    global:
> > > > > > +
> > > > > > +	rte_ring_reset;
> > > > > > +
> > > > > > +};
> > > > >
> > > > > To me, a static inline function does not need to be added in
> > > > > rte_ring_version.map (or is it due to a check script checking the
> > > > > __rte_experimental tag ?). I found at least one commit where it
> > > > > is not the case:
> > > > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > > > >
> > > > > There are 2 options:
> > > > > 1- remove the rte_ring_version.map part of the patch.
> > > > > 2- change the static inline function into a standard function.
> > > > >
> > > > > I would prefer 2-, because it allows to keep an api/abi compat
> > > > > layer in the future.
> > > >
> > > > There are no news about this patch.
> > > > I classify it as changes requested.
> > > >
> > > Sorry for missed your comments for long time, I just submitted v8.
> > > I took the first option as it is in the data path and to keep consistent to its
> > neighboring functions.
> > 
> > Could you give a little more context about why you need to reset
> > the ring in the data path? I see that it is used in rte_hash_reset(),
> > but in my thinking, this was more used at init/exit.
> Sorry,literally it is in the control path, but I was impressed it will impact the 
> Data path performance when discussing this patch with Honnappa. 

I'm asking this because given the recent discussions about ABI stability,
I'd like to avoid defining a new static inline if it is not required.

Thanks,
Olivier
Gavin Hu (Arm Technology China) July 12, 2019, 3:07 p.m. | #7
Hi Olivier,

> -----Original Message-----
> From: Olivier Matz <olivier.matz@6wind.com>
> Sent: Friday, July 12, 2019 7:49 PM
> To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> Cc: thomas@monjalon.net; dev@dpdk.org; nd <nd@arm.com>;
> jerinj@marvell.com; hemant.agrawal@nxp.com; Nipun.gupta@nxp.com;
> Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> i.maximets@samsung.com; stable@dpdk.org; Ruifeng Wang (Arm
> Technology China) <Ruifeng.Wang@arm.com>
> Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> when not in use
> 
> Hi Gavin,
> 
> On Fri, Jul 12, 2019 at 11:06:28AM +0000, Gavin Hu (Arm Technology China)
> wrote:
> > Hi Olivier,
> >
> > > -----Original Message-----
> > > From: Olivier Matz <olivier.matz@6wind.com>
> > > Sent: Friday, July 12, 2019 5:54 PM
> > > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > > Cc: thomas@monjalon.net; dev@dpdk.org; nd <nd@arm.com>;
> > > jerinj@marvell.com; hemant.agrawal@nxp.com; Nipun.gupta@nxp.com;
> > > Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> > > i.maximets@samsung.com; stable@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the
> ring
> > > when not in use
> > >
> > > Hi Gavin,
> > >
> > > On Fri, Jul 12, 2019 at 09:32:39AM +0000, Gavin Hu (Arm Technology
> China)
> > > wrote:
> > > > Hi Olivier and Thomas,
> > > >
> > > > > -----Original Message-----
> > > > > From: Thomas Monjalon <thomas@monjalon.net>
> > > > > Sent: Thursday, July 4, 2019 10:42 PM
> > > > > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>
> > > > > Cc: dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>; nd
> > > > > <nd@arm.com>; jerinj@marvell.com; hemant.agrawal@nxp.com;
> > > > > Nipun.gupta@nxp.com; Honnappa Nagarahalli
> > > > > <Honnappa.Nagarahalli@arm.com>; i.maximets@samsung.com;
> > > > > stable@dpdk.org
> > > > > Subject: Re: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush
> the ring
> > > > > when not in use
> > > > >
> > > > > 29/03/2019 15:17, Olivier Matz:
> > > > > > Hi,
> > > > > >
> > > > > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > > > > Currently, the flush is done by dequeuing the ring in a while loop.
> It is
> > > > > > > much simpler to flush the queue by resetting the head and tail
> indices.
> > > > > > >
> > > > > > > Fixes: af75078fece3 ("first public release")
> > > > > > > Cc: stable@dpdk.org
> > > > > > >
> > > > > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > > > Reviewed-by: Honnappa Nagarahalli
> <honnappa.nagarahalli@arm.com>
> > > > > > > ---
> > > > > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > > > > >  	rte_ring_free;
> > > > > > >
> > > > > > >  } DPDK_2.0;
> > > > > > > +
> > > > > > > +EXPERIMENTAL {
> > > > > > > +    global:
> > > > > > > +
> > > > > > > +	rte_ring_reset;
> > > > > > > +
> > > > > > > +};
> > > > > >
> > > > > > To me, a static inline function does not need to be added in
> > > > > > rte_ring_version.map (or is it due to a check script checking the
> > > > > > __rte_experimental tag ?). I found at least one commit where it
> > > > > > is not the case:
> > > > > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > > > > >
> > > > > > There are 2 options:
> > > > > > 1- remove the rte_ring_version.map part of the patch.
> > > > > > 2- change the static inline function into a standard function.
> > > > > >
> > > > > > I would prefer 2-, because it allows to keep an api/abi compat
> > > > > > layer in the future.
> > > > >
> > > > > There are no news about this patch.
> > > > > I classify it as changes requested.
> > > > >
> > > > Sorry for missed your comments for long time, I just submitted v8.
> > > > I took the first option as it is in the data path and to keep consistent to
> its
> > > neighboring functions.
> > >
> > > Could you give a little more context about why you need to reset
> > > the ring in the data path? I see that it is used in rte_hash_reset(),
> > > but in my thinking, this was more used at init/exit.
> > Sorry,literally it is in the control path, but I was impressed it will impact
> the
> > Data path performance when discussing this patch with Honnappa.
> 
> I'm asking this because given the recent discussions about ABI stability,
> I'd like to avoid defining a new static inline if it is not required.

Ok, will take 2nd option in V9, and squash the two patches into one, otherwise it reports the following error:
"error: ‘rte_ring_reset’ defined but not used [-Werror=unused-function]"

Best regards,
Gavin
Honnappa Nagarahalli July 12, 2019, 3:40 p.m. | #8
<snip>

> > > > > >
> > > > > > 29/03/2019 15:17, Olivier Matz:
> > > > > > > Hi,
> > > > > > >
> > > > > > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > > > > > Currently, the flush is done by dequeuing the ring in a while loop.
> > It is
> > > > > > > > much simpler to flush the queue by resetting the head and
> > > > > > > > tail
> > indices.
> > > > > > > >
> > > > > > > > Fixes: af75078fece3 ("first public release")
> > > > > > > > Cc: stable@dpdk.org
> > > > > > > >
> > > > > > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > > > > Reviewed-by: Honnappa Nagarahalli
> > <honnappa.nagarahalli@arm.com>
> > > > > > > > ---
> > > > > > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > > > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > > > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > > > > > >  	rte_ring_free;
> > > > > > > >
> > > > > > > >  } DPDK_2.0;
> > > > > > > > +
> > > > > > > > +EXPERIMENTAL {
> > > > > > > > +    global:
> > > > > > > > +
> > > > > > > > +	rte_ring_reset;
> > > > > > > > +
> > > > > > > > +};
> > > > > > >
> > > > > > > To me, a static inline function does not need to be added in
> > > > > > > rte_ring_version.map (or is it due to a check script
> > > > > > > checking the __rte_experimental tag ?). I found at least one
> > > > > > > commit where it is not the case:
> > > > > > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > > > > > >
> > > > > > > There are 2 options:
> > > > > > > 1- remove the rte_ring_version.map part of the patch.
> > > > > > > 2- change the static inline function into a standard function.
> > > > > > >
> > > > > > > I would prefer 2-, because it allows to keep an api/abi
> > > > > > > compat layer in the future.
> > > > > >
> > > > > > There are no news about this patch.
> > > > > > I classify it as changes requested.
> > > > > >
> > > > > Sorry for missed your comments for long time, I just submitted v8.
> > > > > I took the first option as it is in the data path and to keep
> > > > > consistent to
> > its
> > > > neighboring functions.
> > > >
> > > > Could you give a little more context about why you need to reset
> > > > the ring in the data path? I see that it is used in
> > > > rte_hash_reset(), but in my thinking, this was more used at init/exit.
> > > Sorry,literally it is in the control path, but I was impressed it
> > > will impact
> > the
> > > Data path performance when discussing this patch with Honnappa.
> >
> > I'm asking this because given the recent discussions about ABI
> > stability, I'd like to avoid defining a new static inline if it is not required.
> 
> Ok, will take 2nd option in V9, and squash the two patches into one, otherwise
> it reports the following error:
> "error: ‘rte_ring_reset’ defined but not used [-Werror=unused-function]"
Agree, it is a control path function, does not impact any data path performance. It should not be inline.

> 
> Best regards,
> Gavin
Gavin Hu (Arm Technology China) July 12, 2019, 4:01 p.m. | #9
> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Friday, July 12, 2019 11:41 PM
> To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>; Olivier Matz
> <olivier.matz@6wind.com>
> Cc: thomas@monjalon.net; dev@dpdk.org; nd <nd@arm.com>;
> jerinj@marvell.com; hemant.agrawal@nxp.com; Nipun.gupta@nxp.com;
> i.maximets@samsung.com; stable@dpdk.org; Ruifeng Wang (Arm
> Technology China) <Ruifeng.Wang@arm.com>; nd <nd@arm.com>
> Subject: RE: [dpdk-dev] [PATCH v7 1/2] ring: add reset API to flush the ring
> when not in use
> 
> <snip>
> 
> > > > > > >
> > > > > > > 29/03/2019 15:17, Olivier Matz:
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > > > > > > > > Currently, the flush is done by dequeuing the ring in a while
> loop.
> > > It is
> > > > > > > > > much simpler to flush the queue by resetting the head and
> > > > > > > > > tail
> > > indices.
> > > > > > > > >
> > > > > > > > > Fixes: af75078fece3 ("first public release")
> > > > > > > > > Cc: stable@dpdk.org
> > > > > > > > >
> > > > > > > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > > > > > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > > > > > Reviewed-by: Honnappa Nagarahalli
> > > <honnappa.nagarahalli@arm.com>
> > > > > > > > > ---
> > > > > > > > > --- a/lib/librte_ring/rte_ring_version.map
> > > > > > > > > +++ b/lib/librte_ring/rte_ring_version.map
> > > > > > > > > @@ -17,3 +17,10 @@ DPDK_2.2 {
> > > > > > > > >  	rte_ring_free;
> > > > > > > > >
> > > > > > > > >  } DPDK_2.0;
> > > > > > > > > +
> > > > > > > > > +EXPERIMENTAL {
> > > > > > > > > +    global:
> > > > > > > > > +
> > > > > > > > > +	rte_ring_reset;
> > > > > > > > > +
> > > > > > > > > +};
> > > > > > > >
> > > > > > > > To me, a static inline function does not need to be added in
> > > > > > > > rte_ring_version.map (or is it due to a check script
> > > > > > > > checking the __rte_experimental tag ?). I found at least one
> > > > > > > > commit where it is not the case:
> > > > > > > > c277b34c1b3b ("mbuf: add function returning buffer address")
> > > > > > > >
> > > > > > > > There are 2 options:
> > > > > > > > 1- remove the rte_ring_version.map part of the patch.
> > > > > > > > 2- change the static inline function into a standard function.
> > > > > > > >
> > > > > > > > I would prefer 2-, because it allows to keep an api/abi
> > > > > > > > compat layer in the future.
> > > > > > >
> > > > > > > There are no news about this patch.
> > > > > > > I classify it as changes requested.
> > > > > > >
> > > > > > Sorry for missed your comments for long time, I just submitted v8.
> > > > > > I took the first option as it is in the data path and to keep
> > > > > > consistent to
> > > its
> > > > > neighboring functions.
> > > > >
> > > > > Could you give a little more context about why you need to reset
> > > > > the ring in the data path? I see that it is used in
> > > > > rte_hash_reset(), but in my thinking, this was more used at init/exit.
> > > > Sorry,literally it is in the control path, but I was impressed it
> > > > will impact
> > > the
> > > > Data path performance when discussing this patch with Honnappa.
> > >
> > > I'm asking this because given the recent discussions about ABI
> > > stability, I'd like to avoid defining a new static inline if it is not required.
> >
> > Ok, will take 2nd option in V9, and squash the two patches into one,
> otherwise
> > it reports the following error:
> > "error: ‘rte_ring_reset’ defined but not used [-Werror=unused-function]"
> Agree, it is a control path function, does not impact any data path
> performance. It should not be inline.
Thanks for your clarification, I submitted v9 for this.
Olivier Matz July 16, 2019, 8:47 a.m. | #10
On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> Currently, the flush is done by dequeuing the ring in a while loop. It is
> much simpler to flush the queue by resetting the head and tail indices.
> 
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

Acked-by: Olivier Matz <olivier.matz@6wind.com>
Olivier Matz July 16, 2019, 9 a.m. | #11
On Tue, Jul 16, 2019 at 10:47:20AM +0200, Olivier Matz wrote:
> On Fri, Mar 15, 2019 at 11:31:25AM +0800, Gavin Hu wrote:
> > Currently, the flush is done by dequeuing the ring in a while loop. It is
> > much simpler to flush the queue by resetting the head and tail indices.
> > 
> > Fixes: af75078fece3 ("first public release")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Sorry, I meant to ack the v9.

Patch

diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index af5444a..2830300 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -671,6 +671,26 @@  rte_ring_dequeue(struct rte_ring *r, void **obj_p)
 }
 
 /**
+ * Flush a ring.
+ *
+ * This function flush all the elements in a ring
+ *
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * @warning
+ * Make sure the ring is not in use while calling this function.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ */
+static inline void __rte_experimental
+rte_ring_reset(struct rte_ring *r)
+{
+	r->prod.head = r->cons.head = 0;
+	r->prod.tail = r->cons.tail = 0;
+}
+
+/**
  * Return the number of entries in a ring.
  *
  * @param r
diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
index d935efd..581d9ca 100644
--- a/lib/librte_ring/rte_ring_version.map
+++ b/lib/librte_ring/rte_ring_version.map
@@ -17,3 +17,10 @@  DPDK_2.2 {
 	rte_ring_free;
 
 } DPDK_2.0;
+
+EXPERIMENTAL {
+    global:
+
+	rte_ring_reset;
+
+};