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From: "Gujjar, Abhinandan S" <abhinandan.gujjar@intel.com>
To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"Richardson, Bruce" <bruce.richardson@intel.com>,
	"Akhil.goyal@nxp.com" <akhil.goyal@nxp.com>,
	Ray Kinsella <mdr@ashroe.eu>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Doherty, Declan" <declan.doherty@intel.com>,
	"techboard@dpdk.org" <techboard@dpdk.org>,
	"Vangati, Narender" <narender.vangati@intel.com>,
	"jerinj@marvell.com" <jerinj@marvell.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [dpdk-techboard] [v4 1/3] cryptodev: support enqueue callback functions
Date: Thu, 29 Oct 2020 13:52:46 +0000
Message-ID: <MWHPR11MB18381B3BDB4A72502EDEDCE6E8140@MWHPR11MB1838.namprd11.prod.outlook.com> (raw)
In-Reply-To: <DBAPR08MB58147711C02EB901451D2AE598170@DBAPR08MB5814.eurprd08.prod.outlook.com>

Hi Akhil,

Any updates on this?

Thanks
Abhinandan

> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Wednesday, October 28, 2020 8:52 PM
> To: Richardson, Bruce <bruce.richardson@intel.com>; Akhil.goyal@nxp.com;
> Ray Kinsella <mdr@ashroe.eu>
> Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Gujjar, Abhinandan S
> <abhinandan.gujjar@intel.com>; dev@dpdk.org; Doherty, Declan
> <declan.doherty@intel.com>; techboard@dpdk.org; Vangati, Narender
> <narender.vangati@intel.com>; jerinj@marvell.com; nd <nd@arm.com>
> Subject: RE: [dpdk-techboard] [v4 1/3] cryptodev: support enqueue callback
> functions
> 
> + Ray for ABI
> 
> <snip>
> 
> >
> > On Wed, Oct 28, 2020 at 02:28:43PM +0000, Akhil Goyal wrote:
> > >
> > > Hi Konstantin,
> > >
> > > > > > Hi Tech board members,
> > > > > >
> > > > > > I have a doubt about the ABI breakage in below addition of field.
> > > > > > Could you please comment.
> > > > > >
> > > > > > >  /** The data structure associated with each crypto device.
> > > > > > > */ struct rte_cryptodev {
> > > > > > >  	dequeue_pkt_burst_t dequeue_burst; @@ -867,6 +922,10
> > @@
> > > > > > > struct rte_cryptodev {
> > > > > > >  	__extension__
> > > > > > >  	uint8_t attached : 1;
> > > > > > >  	/**< Flag indicating the device is attached */
> > > > > > > +
> > > > > > > +	struct rte_cryptodev_enq_cb_rcu *enq_cbs;
> > > > > > > +	/**< User application callback for pre enqueue processing
> > > > > > > +*/
> > > > > > > +
> > > > > > >  } __rte_cache_aligned;
> > > > > >
> > > > > > Here rte_cryptodevs is defined in stable API list in map file
> > > > > > which is a pointer To all rte_cryptodev and the above change
> > > > > > is changing the size of the
> > > > structure.
> > > >
> > > > While this patch adds new fields into rte_cryptodev structure, it
> > > > doesn't change the size of it.
> > > > struct rte_cryptodev is cache line aligned, so it's current size:
> > > > 128B for 64-bit systems, and 64B(/128B) for 32-bit systems.
> > > > So for 64-bit we have 47B implicitly reserved, and for 32-bit we
> > > > have 19B reserved.
> > > > That's enough to add two pointers without changing size of this struct.
> > > >
> > >
> > > The structure is cache aligned, and if the cache line size in 32Byte
> > > and the compilation is done on 64bit machine, then we will be left
> > > with 15Bytes which is not sufficient for 2 pointers.
> > > Do we have such systems? Am I missing something?
> > >
> >
> > I don't think we support any such systems, so unless someone can point
> > out a specific case where we need to support 32-byte CLs, I'd tend
> > towards ignoring this as a non-issue.
> Agree. I have not come across 32B cache line.
> 
> >
> > > The reason I brought this into techboard is to have a consensus on
> > > such change As rte_cryptodev is a very popular and stable structure.
> > > Any changes to it may Have impacts which one person cannot judge all
> > > use
> > cases.
> > >
> >
> > Haven't been tracking this discussion much, but from what I read here,
> > this doesn't look like an ABI break and should be ok.
> If we are filling the holes in the cache line with new fields, it should not be an
> ABI break.
> 
> >
> > Regards,
> > /Bruce

  reply	other threads:[~2020-10-29 13:52 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-25  9:44 [dpdk-dev] [v4 0/3] support enqueue callbacks on cryptodev Abhinandan Gujjar
2020-10-25  9:44 ` [dpdk-dev] [v4 1/3] cryptodev: support enqueue callback functions Abhinandan Gujjar
2020-10-27 12:47   ` Ananyev, Konstantin
2020-10-27 17:16     ` Gujjar, Abhinandan S
2020-10-27 17:20       ` Ananyev, Konstantin
2020-10-27 17:22         ` Gujjar, Abhinandan S
2020-10-27 18:19   ` Akhil Goyal
2020-10-27 19:16     ` Gujjar, Abhinandan S
2020-10-27 19:26       ` Akhil Goyal
2020-10-27 19:41         ` Gujjar, Abhinandan S
2020-10-27 18:28   ` Akhil Goyal
2020-10-28  8:20     ` Gujjar, Abhinandan S
2020-10-28 12:55       ` Ananyev, Konstantin
2020-10-28 14:28         ` Akhil Goyal
2020-10-28 14:52           ` Ananyev, Konstantin
2020-10-28 15:11           ` [dpdk-dev] [dpdk-techboard] " Bruce Richardson
2020-10-28 15:22             ` Honnappa Nagarahalli
2020-10-29 13:52               ` Gujjar, Abhinandan S [this message]
2020-10-29 14:00                 ` Akhil Goyal
2020-10-30  4:24                   ` Gujjar, Abhinandan S
2020-10-30 17:18                     ` Gujjar, Abhinandan S
2020-10-29 14:26               ` Kinsella, Ray
2020-10-25  9:44 ` [dpdk-dev] [v4 2/3] test: add testcase for crypto enqueue callback Abhinandan Gujjar
2020-10-25  9:44 ` [dpdk-dev] [v4 3/3] doc: add enqueue callback APIs Abhinandan Gujjar
2020-10-26 19:08   ` Akhil Goyal
2020-10-27  3:52     ` Gujjar, Abhinandan S
2020-10-27 12:51   ` Ananyev, Konstantin
2020-10-27 17:17     ` Gujjar, Abhinandan S

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