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From: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
To: "Bruce Richardson" <bruce.richardson@intel.com>,
	"Morten Brørup" <mb@smartsharesystems.com>
Cc: Shijith Thotton <sthotton@marvell.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Honnappa.Nagarahalli@arm.com" <Honnappa.Nagarahalli@arm.com>,
	Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
	"olivier.matz@6wind.com" <olivier.matz@6wind.com>,
	"stephen@networkplumber.org" <stephen@networkplumber.org>,
	"thomas@monjalon.net" <thomas@monjalon.net>
Subject: RE: [EXT] Re: [PATCH v1 2/4] mbuf: add second dynamic field member for VA only build
Date: Tue, 30 Aug 2022 08:41:57 +0000	[thread overview]
Message-ID: <PH0PR18MB408665FCDF05C630C7184AE3DE799@PH0PR18MB4086.namprd18.prod.outlook.com> (raw)
In-Reply-To: <Yw3L6tIo82/0gZ1+@bricha3-MOBL.ger.corp.intel.com>



> -----Original Message-----
> From: Bruce Richardson <bruce.richardson@intel.com>
> Sent: Tuesday, August 30, 2022 2:06 PM
> To: Morten Brørup <mb@smartsharesystems.com>
> Cc: Shijith Thotton <sthotton@marvell.com>; dev@dpdk.org; Pavan
> Nikhilesh Bhagavatula <pbhagavatula@marvell.com>;
> Honnappa.Nagarahalli@arm.com; Jerin Jacob Kollanukkaran
> <jerinj@marvell.com>; olivier.matz@6wind.com;
> stephen@networkplumber.org; thomas@monjalon.net
> Subject: [EXT] Re: [PATCH v1 2/4] mbuf: add second dynamic field member
> for VA only build
> 
> External Email
> 
> ----------------------------------------------------------------------
> On Mon, Aug 29, 2022 at 08:32:20PM +0200, Morten Brørup wrote:
> >
> > > From: Shijith Thotton [mailto:sthotton@marvell.com]
> > > Sent: Monday, 29 August 2022 17.16
> > >
> > > mbuf physical address field is not used in builds which only uses VA.
> > > It is used to expand the dynamic field area.
> > >
> > > Signed-off-by: Shijith Thotton <sthotton@marvell.com>
> > > ---
> > >  lib/mbuf/rte_mbuf_core.h | 26 +++++++++++++++++---------
> > >  lib/mbuf/rte_mbuf_dyn.c  |  2 ++
> > >  2 files changed, 19 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
> > > index 81cb07c2e4..98ce62fd6a 100644
> > > --- a/lib/mbuf/rte_mbuf_core.h
> > > +++ b/lib/mbuf/rte_mbuf_core.h
> > > @@ -579,15 +579,23 @@ struct rte_mbuf {
> > >  	RTE_MARKER cacheline0;
> > >
> > >  	void *buf_addr;           /**< Virtual address of segment buffer.
> > > */
> > > -	/**
> > > -	 * Physical address of segment buffer.
> > > -	 * This field is invalid if the build is configured to use only
> > > -	 * virtual address as IOVA (i.e. RTE_IOVA_AS_VA is defined).
> > > -	 * Force alignment to 8-bytes, so as to ensure we have the exact
> > > -	 * same mbuf cacheline0 layout for 32-bit and 64-bit. This makes
> > > -	 * working on vector drivers easier.
> > > -	 */
> > > -	rte_iova_t buf_iova __rte_aligned(sizeof(rte_iova_t));
> > > +	RTE_STD_C11
> > > +	union {
> > > +		/**
> > > +		 * Physical address of segment buffer.
> > > +		 * This field is invalid if the build is configured to use
> > > only
> > > +		 * virtual address as IOVA (i.e. RTE_IOVA_AS_VA is
> > > defined).
> > > +		 * Force alignment to 8-bytes, so as to ensure we have the
> > > exact
> > > +		 * same mbuf cacheline0 layout for 32-bit and 64-bit. This
> > > makes
> > > +		 * working on vector drivers easier.
> > > +		 */
> > > +		rte_iova_t buf_iova __rte_aligned(sizeof(rte_iova_t));
> > > +		/**
> > > +		 * Reserved for dynamic field in builds where physical
> > > address
> > > +		 * field is invalid.
> > > +		 */
> > > +		uint64_t dynfield2;
> > > +	};
> > >
> > >  	/* next 8 bytes are initialised on RX descriptor rearm */
> > >  	RTE_MARKER64 rearm_data;
> >
> > I know that the intention here is to keep the rte_mbuf structure intact,
> which will certainly improve the probability of getting this patch series into
> DPDK.
> >
> > So, I will add a comment for the benefit of the other participants in the
> discussion:
> >
> > With this patch, and in RTE_IOVA_AS_VA mode, it becomes possible to
> move m->next into the first cache line, so rte_pktmbuf_prefree_seg() does
> not have to touch the second cache line, thus potentially improving
> performance by eliminating one cache miss per freed packet segment. (I also
> recall someone mentioning that some PMDs set m->next on RX... If that is
> the case, a cache miss per packet might also be avoidable in those PMDs.)
> >
> > Obviously, moving m->next to the first cache line is not related to this patch
> series, but would belong in a completely different patch.
> >
> 
> +1 to that, with the exception that if it is decided to move the next
> pointer rather than use this as dynamic space, I think it *should* be in
> this patch series, rather than mucking about with mbuf twice. :-)

+1 When RTE_IOVA_AS_VA is set we can set mbuf->next as the dynamic field and move it to mbuf->buf_iova.
mbuf->next write is one of the prominent hotspot in arm platforms.

  reply	other threads:[~2022-08-30  8:42 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-30 16:25 [PATCH] mbuf: add mbuf physical address field to dynamic field Shijith Thotton
2022-06-30 16:45 ` Stephen Hemminger
2022-07-01 12:16   ` Shijith Thotton
2022-07-01 12:24   ` Shijith Thotton
2022-07-03  7:31     ` Morten Brørup
2022-07-04 14:00       ` Bruce Richardson
2022-08-03 15:34         ` [EXT] " Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 0/4] mbuf dynamic field expansion Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 0/5] " Shijith Thotton
2022-09-21  9:43               ` David Marchand
2022-09-21 14:01                 ` [EXT] " Shijith Thotton
2022-09-21 13:56               ` [PATCH v3 " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-28 12:52                   ` Olivier Matz
2022-09-29  5:48                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-28  7:24                   ` Thomas Monjalon
2022-09-28 12:52                     ` Olivier Matz
2022-09-28 19:33                       ` Thomas Monjalon
2022-09-28 19:48                       ` Stephen Hemminger
2022-09-29  6:13                         ` [EXT] " Shijith Thotton
2022-09-28 12:52                   ` Olivier Matz
2022-09-21 13:56                 ` [PATCH v3 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-21 14:07                   ` Morten Brørup
2022-09-28 12:52                   ` Olivier Matz
2022-09-29  6:14                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-28 12:53                   ` Olivier Matz
2022-09-29  6:19                     ` [EXT] " Shijith Thotton
2022-09-29  7:44                       ` Olivier Matz
2022-09-29  8:10                         ` Shijith Thotton
2022-10-07 20:17                   ` Olivier Matz
2022-10-07 20:22                     ` [EXT] " Shijith Thotton
2022-09-21 13:56                 ` [PATCH v3 5/5] drivers: mark software " Shijith Thotton
2022-09-28  5:41                 ` [PATCH v3 0/5] mbuf dynamic field expansion Shijith Thotton
2022-09-28 12:52                 ` Olivier Matz
2022-09-29  4:51                   ` [EXT] " Shijith Thotton
2022-10-07 13:50                 ` Thomas Monjalon
2022-10-07 19:35                   ` [EXT] " Shijith Thotton
2022-10-07 19:30                 ` [PATCH v4 0/7] " Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 20:16                     ` Olivier Matz
2022-10-07 20:20                       ` [EXT] " Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 20:17                     ` Olivier Matz
2022-10-07 19:30                   ` [PATCH v4 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 19:30                   ` [PATCH v4 7/7] drivers: mark software " Shijith Thotton
2022-10-07 20:19                   ` [PATCH v4 0/7] mbuf dynamic field expansion Olivier Matz
2022-10-07 21:02                   ` [PATCH v5 " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 21:20                       ` Stephen Hemminger
2022-10-07 21:02                     ` [PATCH v5 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 21:22                       ` Stephen Hemminger
2022-10-07 21:30                         ` [EXT] " Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 21:02                     ` [PATCH v5 7/7] drivers: mark software " Shijith Thotton
2022-10-09  9:34                     ` [PATCH v5 0/7] mbuf dynamic field expansion Thomas Monjalon
2022-09-07 13:43             ` [PATCH v2 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-07 15:31               ` Stephen Hemminger
2022-09-07 15:38                 ` Bruce Richardson
2022-09-07 21:33                   ` Morten Brørup
2022-09-07 13:43             ` [PATCH v2 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-07 13:43             ` [PATCH v2 5/5] drivers: mark software " Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 1/4] build: add meson option to configure IOVA mode " Shijith Thotton
2022-08-29 18:18             ` Morten Brørup
2022-08-30  8:32               ` Bruce Richardson
2022-08-29 15:16           ` [PATCH v1 2/4] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-08-29 18:32             ` Morten Brørup
2022-08-30  8:35               ` Bruce Richardson
2022-08-30  8:41                 ` Pavan Nikhilesh Bhagavatula [this message]
2022-08-30 13:22                   ` [EXT] " Honnappa Nagarahalli
2022-09-07 13:55                     ` Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 3/4] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-08-29 15:16           ` [PATCH v1 4/4] drivers: mark software " Shijith Thotton
2022-08-30 13:07     ` [PATCH] mbuf: add mbuf physical address field to dynamic field Ferruh Yigit
2022-09-12 13:19       ` [EXT] " Shijith Thotton
2022-06-30 16:55 ` Bruce Richardson
2022-07-01  9:48   ` Olivier Matz
2022-07-01 11:53     ` Slava Ovsiienko
2022-07-01 12:01     ` [EXT] " Shijith Thotton

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