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From: Phil Yang <Phil.Yang@arm.com>
To: "rasland@nvidia.com" <rasland@nvidia.com>,
	"matan@nvidia.com" <matan@nvidia.com>,
	Shahaf Shuler <shahafs@nvidia.com>
Cc: nd <nd@arm.com>, Alexander Kozyrev <akozyrev@nvidia.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"dev@dpdk.org" <dev@dpdk.org>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v4] net/mlx5: relaxed ordering for multi-packet RQ buffer refcnt
Date: Tue, 29 Sep 2020 15:22:52 +0000	[thread overview]
Message-ID: <DB7PR08MB3865DD847236176353ADAC8CE9320@DB7PR08MB3865.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <BN7PR12MB2707C10FFEC23F5296FC6396AF270@BN7PR12MB2707.namprd12.prod.outlook.com>

Hi Raslan,

It seems that there are no more comments for this patch.
So shall we proceed further?

Thanks,
Phil Yang

> -----Original Message-----
> From: Alexander Kozyrev <akozyrev@nvidia.com>
> Sent: Thursday, September 10, 2020 9:37 AM
> To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>; Phil Yang
> <Phil.Yang@arm.com>; akozyrev@mellanox.com; rasland@mellanox.com;
> dev@dpdk.org
> Cc: Phil Yang <Phil.Yang@arm.com>; matan@mellanox.com; Shahaf Shuler
> <shahafs@mellanox.com>; viacheslavo@mellanox.com; nd <nd@arm.com>;
> nd <nd@arm.com>
> Subject: RE: [PATCH v4] net/mlx5: relaxed ordering for multi-packet RQ
> buffer refcnt
> 
> > <snip>
> >
> > >
> > > Use c11 atomics with RELAXED ordering instead of the rte_atomic ops
> > > which enforce unnecessary barriers on aarch64.
> > >
> > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > Looks good.
> >
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> Acked-by: Alexander Kozyrev <akozyrev@nvidia.com>
> 
> >
> > > ---
> > > v4:
> > > Remove the unnecessary ACQUIRE barrier in rx burst path. (Honnappa)
> > >
> > > v3:
> > > Split from the patchset:
> > >
> https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatch
> > >
> >
> work.dpdk.org%2Fcover%2F68159%2F&amp;data=02%7C01%7Cakozyrev%40
> nv
> > idia.
> > >
> >
> com%7Cf16ba4e8cfb145f5d82008d85529348e%7C43083d15727340c1b7db39e
> f
> > d9ccc
> > >
> >
> 17a%7C0%7C0%7C637352982762038088&amp;sdata=0HzTxbzh0Dqk0hZ5PIgE
> V
> > zieyV%
> > > 2BnLTivsVIFFxXFAtI%3D&amp;reserved=0
> > >
> > >  drivers/net/mlx5/mlx5_rxq.c  |  2 +-
> > >  drivers/net/mlx5/mlx5_rxtx.c | 16 +++++++++-------
> > > drivers/net/mlx5/mlx5_rxtx.h |  2 +-
> > >  3 files changed, 11 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
> > > index
> > > 79eb8f8..40e0239 100644
> > > --- a/drivers/net/mlx5/mlx5_rxq.c
> > > +++ b/drivers/net/mlx5/mlx5_rxq.c
> > > @@ -2012,7 +2012,7 @@ mlx5_mprq_buf_init(struct rte_mempool *mp,
> void
> > > *opaque_arg,
> > >
> > >  	memset(_m, 0, sizeof(*buf));
> > >  	buf->mp = mp;
> > > -	rte_atomic16_set(&buf->refcnt, 1);
> > > +	__atomic_store_n(&buf->refcnt, 1, __ATOMIC_RELAXED);
> > >  	for (j = 0; j != strd_n; ++j) {
> > >  		shinfo = &buf->shinfos[j];
> > >  		shinfo->free_cb = mlx5_mprq_buf_free_cb; diff --git
> > > a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c index
> > > 1b71e94..549477b 100644
> > > --- a/drivers/net/mlx5/mlx5_rxtx.c
> > > +++ b/drivers/net/mlx5/mlx5_rxtx.c
> > > @@ -1626,10 +1626,11 @@ mlx5_mprq_buf_free_cb(void *addr
> > __rte_unused,
> > > void *opaque)  {
> > >  	struct mlx5_mprq_buf *buf = opaque;
> > >
> > > -	if (rte_atomic16_read(&buf->refcnt) == 1) {
> > > +	if (__atomic_load_n(&buf->refcnt, __ATOMIC_RELAXED) == 1) {
> > >  		rte_mempool_put(buf->mp, buf);
> > > -	} else if (rte_atomic16_add_return(&buf->refcnt, -1) == 0) {
> > > -		rte_atomic16_set(&buf->refcnt, 1);
> > > +	} else if (unlikely(__atomic_sub_fetch(&buf->refcnt, 1,
> > > +					       __ATOMIC_RELAXED) == 0)) {
> > > +		__atomic_store_n(&buf->refcnt, 1, __ATOMIC_RELAXED);
> > >  		rte_mempool_put(buf->mp, buf);
> > >  	}
> > >  }
> > > @@ -1709,7 +1710,8 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct
> > > rte_mbuf **pkts, uint16_t pkts_n)
> > >
> > >  		if (consumed_strd == strd_n) {
> > >  			/* Replace WQE only if the buffer is still in use. */
> > > -			if (rte_atomic16_read(&buf->refcnt) > 1) {
> > > +			if (__atomic_load_n(&buf->refcnt,
> > > +					    __ATOMIC_RELAXED) > 1) {
> > >  				mprq_buf_replace(rxq, rq_ci & wq_mask,
> > strd_n);
> > >  				/* Release the old buffer. */
> > >  				mlx5_mprq_buf_free(buf);
> > > @@ -1821,9 +1823,9 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct
> > > rte_mbuf **pkts, uint16_t pkts_n)
> > >  			void *buf_addr;
> > >
> > >  			/* Increment the refcnt of the whole chunk. */
> > > -			rte_atomic16_add_return(&buf->refcnt, 1);
> > > -			MLX5_ASSERT((uint16_t)rte_atomic16_read(&buf-
> > > >refcnt) <=
> > > -				    strd_n + 1);
> > > +			__atomic_add_fetch(&buf->refcnt, 1,
> > > __ATOMIC_RELAXED);
> > > +			MLX5_ASSERT(__atomic_load_n(&buf->refcnt,
> > > +				    __ATOMIC_RELAXED) <= strd_n + 1);
> > >  			buf_addr = RTE_PTR_SUB(addr,
> > > RTE_PKTMBUF_HEADROOM);
> > >  			/*
> > >  			 * MLX5 device doesn't use iova but it is necessary in
> a
> > diff
> > > --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
> > > index c02a007..467f31d 100644
> > > --- a/drivers/net/mlx5/mlx5_rxtx.h
> > > +++ b/drivers/net/mlx5/mlx5_rxtx.h
> > > @@ -68,7 +68,7 @@ struct rxq_zip {
> > >  /* Multi-Packet RQ buffer header. */
> > >  struct mlx5_mprq_buf {
> > >  	struct rte_mempool *mp;
> > > -	rte_atomic16_t refcnt; /* Atomically accessed refcnt. */
> > > +	uint16_t refcnt; /* Atomically accessed refcnt. */
> > >  	uint8_t pad[RTE_PKTMBUF_HEADROOM]; /* Headroom for the first
> > packet.
> > > */
> > >  	struct rte_mbuf_ext_shared_info shinfos[];
> > >  	/*
> > > --
> > > 2.7.4


  reply	other threads:[~2020-09-29 15:23 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13 12:38 [dpdk-dev] [PATCH RFC v1 0/6] barrier fix and optimization for mlx5 on aarch64 Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 1/6] net/mlx5: relax the barrier for UAR write Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 2/6] net/mlx5: use cio barrier before the BF WQE Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 3/6] net/mlx5: add missing barrier Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 4/6] net/mlx5: add descriptive comment for a barrier Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 5/6] net/mlx5: non-cacheable mapping defaulted for aarch64 Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 6/6] net/mlx5: relaxed ordering for multi-packet RQ buffer refcnt Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 0/7] introduce new barrier class and use it for mlx5 PMD Gavin Hu
2020-04-10 17:20   ` Andrew Rybchenko
2020-04-11  3:46     ` Gavin Hu
2020-04-13  9:51       ` Andrew Rybchenko
2020-04-13 16:46         ` Gavin Hu
2020-05-11 18:06   ` [dpdk-dev] [RFC] eal: adjust barriers for IO on Armv8-a Honnappa Nagarahalli
2020-05-12  6:18     ` Ruifeng Wang
2020-05-12  6:42       ` Jerin Jacob
2020-05-12  8:02         ` Ruifeng Wang
2020-05-12  8:28           ` Jerin Jacob
2020-05-12 21:44           ` Honnappa Nagarahalli
2020-05-13 14:49             ` Jerin Jacob
2020-05-14  1:02               ` Honnappa Nagarahalli
2020-06-27 19:12   ` [dpdk-dev] [PATCH v2] " Honnappa Nagarahalli
2020-06-27 19:25     ` Honnappa Nagarahalli
2020-06-30  5:13       ` Jerin Jacob
2020-07-03 18:57   ` [dpdk-dev] [PATCH v3 1/3] " Honnappa Nagarahalli
2020-07-03 18:57     ` [dpdk-dev] [PATCH v3 2/3] doc: update armv8-a IO barrier changes Honnappa Nagarahalli
2020-07-05  0:57       ` Jerin Jacob
2020-07-03 18:57     ` [dpdk-dev] [PATCH v3 3/3] doc: update deprecation of CIO barrier APIs Honnappa Nagarahalli
2020-07-05  0:57       ` Jerin Jacob
2020-07-07 20:19       ` Ajit Khaparde
2020-07-08 11:05       ` Ananyev, Konstantin
2020-07-06 23:43   ` [dpdk-dev] [PATCH v4 1/3] eal: adjust barriers for IO on Armv8-a Honnappa Nagarahalli
2020-07-06 23:43     ` [dpdk-dev] [PATCH v4 2/3] doc: update armv8-a IO barrier changes Honnappa Nagarahalli
2020-07-07  8:36       ` David Marchand
2020-07-07 18:37         ` Honnappa Nagarahalli
2020-07-06 23:43     ` [dpdk-dev] [PATCH v4 3/3] doc: update deprecation of CIO barrier APIs Honnappa Nagarahalli
2020-07-07  8:39       ` David Marchand
2020-07-07 20:14       ` David Christensen
2020-07-08 11:49       ` David Marchand
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 1/7] eal: introduce new class of barriers for DMA use cases Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 2/7] net/mlx5: dmb for immediate doorbell ring on aarch64 Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 3/7] net/mlx5: relax barrier to order UAR writes " Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 4/7] net/mlx5: relax barrier for aarch64 Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 5/7] net/mlx5: add descriptive comment for a barrier Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 6/7] net/mlx5: relax ordering for multi-packet RQ buffer refcnt Gavin Hu
2020-06-23  8:26   ` [dpdk-dev] [PATCH v3] net/mlx5: relaxed " Phil Yang
2020-07-13  3:02     ` Phil Yang
2020-07-20 23:21       ` Alexander Kozyrev
2020-07-21  1:55         ` Phil Yang
2020-07-21  3:58           ` Alexander Kozyrev
2020-07-21  4:03             ` Honnappa Nagarahalli
2020-07-21  4:11               ` Alexander Kozyrev
2020-07-22 12:06                 ` Phil Yang
2020-07-23  4:47         ` Honnappa Nagarahalli
2020-07-23  6:11           ` Phil Yang
2020-07-23 16:53             ` Alexander Kozyrev
2020-07-27 14:52               ` Phil Yang
2020-08-06  2:43                 ` Alexander Kozyrev
2020-08-11  5:20                   ` Honnappa Nagarahalli
2020-09-02 21:52                     ` Alexander Kozyrev
2020-09-03  2:55                       ` Phil Yang
2020-09-09 13:29                         ` Alexander Kozyrev
2020-09-10  1:34                           ` Honnappa Nagarahalli
2020-09-03  2:53     ` [dpdk-dev] [PATCH v4] " Phil Yang
2020-09-10  1:30       ` Honnappa Nagarahalli
2020-09-10  1:36         ` Alexander Kozyrev
2020-09-29 15:22           ` Phil Yang [this message]
2020-09-30 12:44             ` Slava Ovsiienko
2020-09-30 12:52               ` Raslan Darawsheh
2020-09-30 13:57       ` Raslan Darawsheh
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 7/7] doc: clarify one configuration in mlx5 guide Gavin Hu

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