DPDK patches and discussions
 help / color / mirror / Atom feed
From: Jerin Jacob <jerinjacobk@gmail.com>
To: "Coyle, David" <david.coyle@intel.com>
Cc: dpdk-dev <dev@dpdk.org>,
	"Doherty, Declan" <declan.doherty@intel.com>,
	 "Trahe, Fiona" <fiona.trahe@intel.com>
Subject: Re: [dpdk-dev] [RFC] Accelerator API to chain packet processing functions
Date: Fri, 7 Feb 2020 19:48:17 +0530	[thread overview]
Message-ID: <CALBAE1N6gBAtR+GaVUUnsCLr+cK+4E-J7ASXK88KPimpnig77w@mail.gmail.com> (raw)
In-Reply-To: <SN6PR11MB308670D0FF44DE39B477188DE31C0@SN6PR11MB3086.namprd11.prod.outlook.com>

On Fri, Feb 7, 2020 at 6:08 PM Coyle, David <david.coyle@intel.com> wrote:
>
> Hi Jerin, see below

Hi David,

> >
> > On Thu, Feb 6, 2020 at 10:01 PM Coyle, David <david.coyle@intel.com>
> > wrote:
> >

> >
> > There is a risk in drafting API that meant for HW without any HW exists.
> > Because there could be inefficiency on the metadata and fast path API for
> > both models.
> > For example, In the case of CPU based scheme, it will be pure overhead
> > emulate the "queue"(the enqueue and dequeue) for the sake of abstraction
> > where CPU works better in the synchronous model and I have doubt that the
> > session-based scheme will work for HW or not as both difference  HW needs
> > to work hand in hand(IOMMU aspects for two PCI device)
>
> [DC] I understand what you are saying about the overhead of emulating the "sw queue" but this same model is already used in many of the existing device PMDs.
> In the case of SW devices, such as AESNI-MB or NULL for crypto or zlib for compression, the enqueue/dequeue in the PMD is emulated through an rte_ring which is very efficient.
> The accelerator API will use the existing device PMDs so keeping the same model seems like a sensible approach.

In this release, we added CPU crypto support in cryptodev to support
the synchronous model to fix the overhead.

>
> From an application's point of view, this abstraction of the underlying device type is important for usability and maintainability -  the application doesn't need to know
> the device type as such and therefore doesn't need to make different API calls.
>
> The enqueue/dequeue type API was also used with QAT in mind. While QAT HW doesn't support these xform chains at the moment, it could potentially do so in the future.
> As a side note, as part of the work of adding the accelerator API, the QAT PMD will be updated to support the DOCSIS Crypto-CRC accelerator xform chain, where the Crypto
> is done on QAT HW and the CRC will be done in SW, most likely through a call to the optimized rte_net_crc library. This will give a consistent API for the DOCSIS-MAC data-plane
> pipeline prototype we have developed, which uses both AESNI-MB and QAT for benchmarks.
>
> We will take your feedback on the enqueue/dequeue approach for SW devices into consideration though during development.
>
> Finally, I'm unsure what you mean by this line:
>
>         "I have doubt that the session-based scheme will work for HW or not as both difference  HW needs to work hand in hand(IOMMU aspects for two PCI device)"
>
> What do mean by different HW working "hand in hand" and "two PCI device"?
> The intention is that 1 HW device (or it's PMD) would have to support the accel xform chain

I was thinking, it will be N PCIe devices that create the chain. Each
distinct PCI device does the fixed-function and chains them together.

I do understand the usage of QAT HW and CRC in SW.
So If I understand it correctly, in rte_security, we are combining
rte_ethdev and rte_cryptodev. With this spec, we are trying to
combine,
rte_cryptodev and rte_compressdev. So it looks good to me. My only
remaining concern is the name of this API, accelerator too generic
name. IMO, like rte_security, we may need to give more meaningful name
for the use case where crytodev and compressdev can work together.

  reply	other threads:[~2020-02-07 14:18 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-04 14:45 David Coyle
2020-02-04 19:52 ` Jerin Jacob
2020-02-06 10:04   ` Coyle, David
2020-02-06 10:54     ` Jerin Jacob
2020-02-06 16:31       ` Coyle, David
2020-02-06 17:13         ` Jerin Jacob
2020-02-07 12:38           ` Coyle, David
2020-02-07 14:18             ` Jerin Jacob [this message]
2020-02-07 20:34               ` Stephen Hemminger
2020-02-08  7:22                 ` Jerin Jacob
2020-03-05 17:01                   ` Coyle, David
2020-03-06  8:43                     ` Jerin Jacob
2020-02-13 11:50               ` Doherty, Declan
2020-02-18  5:15                 ` Jerin Jacob
2020-02-13 11:44           ` Doherty, Declan
2020-02-18  5:30             ` Jerin Jacob
2020-02-13 11:31       ` Doherty, Declan
2020-02-18  5:12         ` Jerin Jacob
2020-03-05 16:44 Coyle, David
2020-03-06  9:06 ` Jerin Jacob
2020-03-06 14:55   ` Coyle, David
2020-03-06 16:22     ` Jerin Jacob
2020-03-13 18:00       ` Coyle, David
2020-03-13 18:03         ` Jerin Jacob

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CALBAE1N6gBAtR+GaVUUnsCLr+cK+4E-J7ASXK88KPimpnig77w@mail.gmail.com \
    --to=jerinjacobk@gmail.com \
    --cc=david.coyle@intel.com \
    --cc=declan.doherty@intel.com \
    --cc=dev@dpdk.org \
    --cc=fiona.trahe@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).