From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [RFC PATCH 0/3] *** SUBJECT HERE ***
Date: Fri, 1 Dec 2017 14:56:02 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB9772585FAC37D0@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <1512139682-11114-1-git-send-email-konstantin.ananyev@intel.com>
Oops sorry, resending with proper subject.
> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Friday, December 1, 2017 2:48 PM
> To: dev@dpdk.org; dev@dpdk.org
> Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>
> Subject: [RFC PATCH 0/3] *** SUBJECT HERE ***
>
> The series introduces 2 main changes:
>
> 1.Introduce a separate data structure (rte_eth_queue_local)
> to store local to given process (i.e. no-shareable) information
> for each configured rx/tx queue.
> Memory for that structure is allocated/freed dynamically during
> rte_eth_dev_configure().
> Reserve a space for queue specific (rx|tx)_pkt_burst(),
> tx_pkt_prepare() function pointers inside that structure.
> Move rx/tx callback related information inside that structure.
> That introduces a change in current behavior: all callbacks for
> un-configured queues will be automatically removed.
> Also as size of struct rte_eth_dev changes that patch is an ABI breakage,
> so deprecation notice for 18.05 is filled.
> Further suggestions how to introduce the same functionality
> without ABI breakage are welcome.
>
> 2. Make it safe to remove rx/tx callback at runtime.
> Right now it is not possible for the application to figure out
> when it is safe to free removed callback handle and
> associated with it resources(unless the queue is stopped).
> That's probably not a big problem if all callbacks are static
> hange through whole application lifetime)
> and/or application doesn't allocate any resources for the callback handler.
> Though if callbacks have to be added/removed dynamically and
> callback handler would require more resources to operate properly -
> then it might become an issue.
> So patch #2 fixes that problem - now as soon as
> rte_eth_remove_(rx|tx)_callback() completes successfully, application
> can safely free all associated with the removed callback resources.
>
> Performance impact:
> If application doesn't use RX/TX callbacks, then the tests I run didn't
> reveal any performance degradation.
> Though if application do use RX/TX callbacks - patch #2 does introduce
> some slowdown.
>
> To be more specific here, on BDW (E5-2699 v4) 2.2GHz, 4x10Gb (X520-4)
> with http://dpdk.org/dev/patchwork/patch/31864/ patch installed I got:
> 1) testpmd ... --latencystats=1 - slowdown < 1%
> 2) examples//l3fwd ... --parse-ptype - - slowdown < 1%
> 3) examples/rxtx_callbacks - slowdown ~8%
> All that in terms of packet throughput (Mpps).
>
> Ability to safely remove callbacks at runtime implies
> some sort of synchronization.
> Even I tried to make it as light as possible,
> probably some slowdown is unavoidable.
> Of course instead of introducing these changes at rte_ethdev layer
> similar technique could be applied on individual callback basis.
> In that case it would be up to callback writer/installer to decide
> does he/she need a removable at runtime callback or not.
> Though in that case, each installed callback might introduce extra
> synchronization overhead and slowdown.
>
> Konstantin Ananyev (3):
> ethdev: introduce eth_queue_local
> ethdev: make it safe to remove rx/tx callback at runtime
> doc: ethdev ABI change deprecation notice
>
> doc/guides/rel_notes/deprecation.rst | 5 +
> lib/librte_ether/rte_ethdev.c | 390 ++++++++++++++++++++++-------------
> lib/librte_ether/rte_ethdev.h | 174 ++++++++++++----
> 3 files changed, 387 insertions(+), 182 deletions(-)
>
> --
> 2.13.5
prev parent reply other threads:[~2017-12-01 14:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 14:47 Konstantin Ananyev
2017-12-01 14:48 ` [dpdk-dev] [RFC PATCH 1/3] ethdev: introduce eth_queue_local Konstantin Ananyev
2017-12-01 14:48 ` [dpdk-dev] [RFC PATCH 2/3] ethdev: make it safe to remove rx/tx callback at runtime Konstantin Ananyev
2017-12-01 14:48 ` [dpdk-dev] [RFC PATCH 3/3] doc: ethdev ABI change deprecation notice Konstantin Ananyev
2017-12-12 14:55 ` Kovacevic, Marko
2017-12-01 14:56 ` Ananyev, Konstantin [this message]
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=2601191342CEEE43887BDE71AB9772585FAC37D0@irsmsx105.ger.corp.intel.com \
--to=konstantin.ananyev@intel.com \
--cc=dev@dpdk.org \
/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).