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From: Ray Kinsella <mdr@ashroe.eu>
To: Stephen Hemminger <stephen@networkplumber.org>,
	Jerin Jacob Kollanukkaran <jerinj@marvell.com>
Cc: Bruce Richardson <bruce.richardson@intel.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	"thomas@monjalon.net" <thomas@monjalon.net>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] ABI and inline functions
Date: Tue, 23 Apr 2019 15:19:04 +0100	[thread overview]
Message-ID: <c0eadddf-be4b-e0ed-56ba-d98b09769ea5@ashroe.eu> (raw)
Message-ID: <20190423141904.sko_PJ37WXDg-4fLhVA-fCupkpzWAI6XBRIhZk_Xhrc@z> (raw)
In-Reply-To: <20190417115110.5cb70832@hermes.lan>



On 17/04/2019 19:51, Stephen Hemminger wrote:
> On Wed, 17 Apr 2019 17:46:34 +0000
> Jerin Jacob Kollanukkaran <jerinj@marvell.com> wrote:
> 
>>> -----Original Message-----
>>> From: dev <dev-bounces@dpdk.org> On Behalf Of Bruce Richardson
>>> Sent: Wednesday, April 17, 2019 2:07 PM
>>> To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
>>> Cc: dev@dpdk.org; Stephen Hemminger <stephen@networkplumber.org>;
>>> Ananyev, Konstantin <konstantin.ananyev@intel.com>; thomas@monjalon.net;
>>> Ray Kinsella <mdr@ashroe.eu>; nd <nd@arm.com>
>>> Subject: Re: [dpdk-dev] ABI and inline functions
>>>   
>>>> 2) Every function that is not in the direct datapath (fastpath?)
>>>> should not be inline. Exceptions or things like rx/tx burst, ring
>>>> enqueue/dequeue, and packet alloc/free - Stephen  
>>>
>>> Agree with this. Anything not data path should not be inline. The next question
>>> then is for data path items how to determine whether they need to be inline or
>>> not. In general my rule-of-thumb:
>>> * anything dealing with bursts of packets should not be inline  
>>
>> # I think, we need consider the how fat is the function too,
>> If it is light weight, probably we need to make it inline

Well if it light weight however it is not dealing directly with packets,
probably does not matter if is not-inline?

>> # Except the forward case, In real world use case, it is not trivial make large 
>> burst of packet to process it even though function prototype burst.
>> We may need to consider that

>> # For the given function if some argument is used with inline other function,
>>  probably no point in making that function alone  inline as the structure 
>> is exposed in some other function.
>>
>>> * anything what works with single packet at a time should be inline
>>>   
>>>> In this context, does it make sense to say that we will maintain API
>>>> compatibility rather than saying ABI compatibility? This will also
>>>> send the right message to the end users.
>>>>  
>>> I would value ABI compatibility much higher than API compatibility. If someone
>>> is recompiling the application anyway, making a couple of small changes (large
>>> rework is obviously a different issue) to the code should not be a massive issue, I
>>> hope. On the other hand, ABI compatibility is needed to allow seamless update
>>> from one version to another, and it's that ABI compatiblity that allows distro's to
>>> pick up our latest and greatest versions.  
>>
>> IMO, We have two primary use case for DPDK
>>
>> 1) NFV kind of use case 	where the application needs to run on multiple platform
>> without recompiling it.
>> 2) Fixed appliance use case where embed SoC like Intel Denverton or ARM64 integrated
>> Controller used. For fixed appliance use case, end user care more of performance
>> than ABI compatibility as it easy to recompile the end user application vs the cost of
>> hitting performance impact.
> 
> Nobody cares about compatiablity until they have to the first security update.
>  
+1

  parent reply	other threads:[~2019-04-23 14:19 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-17  5:12 Honnappa Nagarahalli
2019-04-17  5:12 ` Honnappa Nagarahalli
2019-04-17  8:36 ` Bruce Richardson
2019-04-17  8:36   ` Bruce Richardson
2019-04-17 16:52   ` Stephen Hemminger
2019-04-17 16:52     ` Stephen Hemminger
2019-04-17 17:46   ` Jerin Jacob Kollanukkaran
2019-04-17 17:46     ` Jerin Jacob Kollanukkaran
2019-04-17 18:51     ` Stephen Hemminger
2019-04-17 18:51       ` Stephen Hemminger
2019-04-18  5:56       ` [dpdk-dev] [EXT] " Jerin Jacob Kollanukkaran
2019-04-18  5:56         ` Jerin Jacob Kollanukkaran
2019-04-23 14:23         ` Ray Kinsella
2019-04-23 14:23           ` Ray Kinsella
2019-04-24 18:38           ` Jerin Jacob Kollanukkaran
2019-04-24 18:38             ` Jerin Jacob Kollanukkaran
2019-04-23 14:19       ` Ray Kinsella [this message]
2019-04-23 14:19         ` [dpdk-dev] " Ray Kinsella
2019-04-18  4:34   ` Honnappa Nagarahalli
2019-04-18  4:34     ` Honnappa Nagarahalli
2019-04-18 10:28     ` Bruce Richardson
2019-04-18 10:28       ` Bruce Richardson
2019-04-23 14:12       ` Ray Kinsella
2019-04-23 14:12         ` Ray Kinsella
2019-04-24  5:15         ` Honnappa Nagarahalli
2019-04-24  5:15           ` Honnappa Nagarahalli
2019-04-24 11:08         ` Burakov, Anatoly
2019-04-24 11:08           ` Burakov, Anatoly
2019-04-24 12:22           ` Ray Kinsella
2019-04-24 12:22             ` Ray Kinsella
2019-04-24 12:54             ` Burakov, Anatoly
2019-04-24 12:54               ` Burakov, Anatoly
2019-04-24 15:44               ` Stephen Hemminger
2019-04-24 15:44                 ` Stephen Hemminger
2019-04-30  8:52             ` Thomas Monjalon
2019-04-30  8:52               ` Thomas Monjalon
2019-04-24  5:08       ` Honnappa Nagarahalli
2019-04-24  5:08         ` Honnappa Nagarahalli
2019-04-24  8:49         ` Bruce Richardson
2019-04-24  8:49           ` Bruce Richardson

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