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From: "McDaniel, Timothy" <timothy.mcdaniel@intel.com>
To: Jerin Jacob <jerinjacobk@gmail.com>, Ray Kinsella <mdr@ashroe.eu>,
	"Neil Horman" <nhorman@tuxdriver.com>
Cc: Jerin Jacob <jerinj@marvell.com>,
	Mattias Rönnblom <mattias.ronnblom@ericsson.com>,
	dpdk-dev <dev@dpdk.org>, "Eads, Gage" <gage.eads@intel.com>,
	"Van Haaren, Harry" <harry.van.haaren@intel.com>
Subject: Re: [dpdk-dev] [PATCH 01/27] eventdev: dlb upstream prerequisites
Date: Mon, 29 Jun 2020 19:30:59 +0000
Message-ID: <BL0PR11MB3090CCAAB60AC90DF8B67CA59E6E0@BL0PR11MB3090.namprd11.prod.outlook.com> (raw)
In-Reply-To: <CALBAE1NkL=zBYLErRCbbp9SiFCLamf0RVbnBz_wvXUdUtX4nCw@mail.gmail.com>

-----Original Message-----
From: Jerin Jacob <jerinjacobk@gmail.com> 
Sent: Saturday, June 27, 2020 2:45 AM
To: McDaniel, Timothy <timothy.mcdaniel@intel.com>; Ray Kinsella <mdr@ashroe.eu>; Neil Horman <nhorman@tuxdriver.com>
Cc: Jerin Jacob <jerinj@marvell.com>; Mattias Rönnblom <mattias.ronnblom@ericsson.com>; dpdk-dev <dev@dpdk.org>; Eads, Gage <gage.eads@intel.com>; Van Haaren, Harry <harry.van.haaren@intel.com>
Subject: Re: [dpdk-dev] [PATCH 01/27] eventdev: dlb upstream prerequisites

> +
> +/** Event port configuration structure */
> +struct rte_event_port_conf_v20 {
> +       int32_t new_event_threshold;
> +       /**< A backpressure threshold for new event enqueues on this port.
> +        * Use for *closed system* event dev where event capacity is limited,
> +        * and cannot exceed the capacity of the event dev.
> +        * Configuring ports with different thresholds can make higher priority
> +        * traffic less likely to  be backpressured.
> +        * For example, a port used to inject NIC Rx packets into the event dev
> +        * can have a lower threshold so as not to overwhelm the device,
> +        * while ports used for worker pools can have a higher threshold.
> +        * This value cannot exceed the *nb_events_limit*
> +        * which was previously supplied to rte_event_dev_configure().
> +        * This should be set to '-1' for *open system*.
> +        */
> +       uint16_t dequeue_depth;
> +       /**< Configure number of bulk dequeues for this event port.
> +        * This value cannot exceed the *nb_event_port_dequeue_depth*
> +        * which previously supplied to rte_event_dev_configure().
> +        * Ignored when device is not RTE_EVENT_DEV_CAP_BURST_MODE capable.
> +        */
> +       uint16_t enqueue_depth;
> +       /**< Configure number of bulk enqueues for this event port.
> +        * This value cannot exceed the *nb_event_port_enqueue_depth*
> +        * which previously supplied to rte_event_dev_configure().
> +        * Ignored when device is not RTE_EVENT_DEV_CAP_BURST_MODE capable.
> +        */
>         uint8_t disable_implicit_release;
>         /**< Configure the port not to release outstanding events in
>          * rte_event_dev_dequeue_burst(). If true, all events received through
> @@ -733,6 +911,14 @@ struct rte_event_port_conf {
>  rte_event_port_default_conf_get(uint8_t dev_id, uint8_t port_id,
>                                 struct rte_event_port_conf *port_conf);
>
> +int
> +rte_event_port_default_conf_get_v20(uint8_t dev_id, uint8_t port_id,
> +                               struct rte_event_port_conf_v20 *port_conf);
> +
> +int
> +rte_event_port_default_conf_get_v21(uint8_t dev_id, uint8_t port_id,
> +                                     struct rte_event_port_conf *port_conf);

Hi Timothy,

+ ABI Maintainers (Ray, Neil)

# As per my understanding, the structures can not be versioned, only
function can be versioned.
i.e we can not make any change to " struct rte_event_port_conf"

# We have a similar case with ethdev and it deferred to next release v20.11
http://patches.dpdk.org/patch/69113/

Regarding the API changes:
# The slow path changes general looks good to me. I will review the
next level in the coming days
# The following fast path changes bothers to me. Could you share more
details on below change?

diff --git a/app/test-eventdev/test_order_atq.c
b/app/test-eventdev/test_order_atq.c
index 3366cfc..8246b96 100644
--- a/app/test-eventdev/test_order_atq.c
+++ b/app/test-eventdev/test_order_atq.c
@@ -34,6 +34,8 @@
                        continue;
                }

+               ev.flow_id = ev.mbuf->udata64;
+
# Since RC1 is near, I am not sure how to accommodate the API changes
now and sort out ABI stuffs.
# Other concern is eventdev spec get bloated with versioning files
just for ONE release as 20.11 will be OK to change the ABI.
# While we discuss the API change, Please send deprecation notice for
ABI change for 20.11,
so that there is no ambiguity of this patch for the 20.11 release.

Hello Jerin,

Thank you for the review comments.

With regard to your comments regarding the fast path flow_id change, the Intel DLB hardware
is not capable of transferring the flow_id as part of the event itself. We therefore require a mechanism
to accomplish this. What we have done to work around this is to require the application to embed the flow_id
within the data payload. The new flag, #define RTE_EVENT_DEV_CAP_CARRY_FLOW_ID (1ULL << 9), can be used
by applications to determine if they need to embed the flow_id, or if its automatically propagated and present in the
received event.

What we should have done is to wrap the assignment with a conditional.  

if (!(device_capability_flags & RTE_EVENT_DEV_CAP_CARRY_FLOW_ID))
	ev.flow_id = ev.mbuf->udata64;

This would minimize/eliminate any performance impact due to the processor's branch prediction logic.
The assignment then becomes in essence a NOOP for all event devices that are capable of carrying the flow_id as part of the event payload itself.

Thanks,
Tim



Thanks,
Tim

  reply index

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-27  4:37 [dpdk-dev] [PATCH 00/27] event/dlb Intel DLB PMD Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 01/27] eventdev: dlb upstream prerequisites Tim McDaniel
2020-06-27  7:44   ` Jerin Jacob
2020-06-29 19:30     ` McDaniel, Timothy [this message]
2020-06-30  4:21       ` Jerin Jacob
2020-06-30 15:37         ` McDaniel, Timothy
2020-06-30 15:57           ` Jerin Jacob
2020-06-30 19:26             ` McDaniel, Timothy
2020-06-30 20:40               ` Pavan Nikhilesh Bhagavatula
2020-06-30 21:07                 ` McDaniel, Timothy
2020-07-01  4:50               ` Jerin Jacob
2020-07-01 16:48                 ` McDaniel, Timothy
2020-06-30 11:22     ` Kinsella, Ray
2020-06-30 11:30       ` Jerin Jacob
2020-06-30 11:36         ` Kinsella, Ray
2020-06-30 12:14           ` Jerin Jacob
2020-07-02 15:21             ` Kinsella, Ray
2020-07-02 16:35               ` McDaniel, Timothy
2020-06-27  4:37 ` [dpdk-dev] [PATCH 02/27] eventdev: do not pass disable_implicit_release bit to trace macro Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 03/27] event/dlb: add shared code version 10.7.9 Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 04/27] event/dlb: add make and meson build infrastructure Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 05/27] event/dlb: add DLB documentation Tim McDaniel
2020-07-09  3:29   ` Eads, Gage
2020-06-27  4:37 ` [dpdk-dev] [PATCH 06/27] event/dlb: add dynamic logging Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 07/27] event/dlb: add private data structures and constants Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 08/27] event/dlb: add definitions shared with LKM or shared code Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 09/27] event/dlb: add inline functions used in multiple files Tim McDaniel
2020-07-07 12:02   ` Bruce Richardson
2020-07-07 14:33     ` McDaniel, Timothy
2020-06-27  4:37 ` [dpdk-dev] [PATCH 10/27] event/dlb: add PFPMD-specific interface layer to shared code Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 11/27] event/dlb: add flexible PMD to device interfaces Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 12/27] event/dlb: add the PMD's public interfaces Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 13/27] event/dlb: add xstats support Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 14/27] event/dlb: add PMD self-tests Tim McDaniel
2020-07-10 20:42   ` Eads, Gage
2020-07-29 18:56     ` McDaniel, Timothy
2020-06-27  4:37 ` [dpdk-dev] [PATCH 15/27] event/dlb: add probe Tim McDaniel
2020-07-09  3:45   ` Eads, Gage
2020-06-27  4:37 ` [dpdk-dev] [PATCH 16/27] event/dlb: add infos_get and configure Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 17/27] event/dlb: add queue_def_conf and port_def_conf Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 18/27] event/dlb: add queue setup Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 19/27] event/dlb: add port_setup Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 20/27] event/dlb: add port_link Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 21/27] event/dlb: add queue_release and port_release Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 22/27] event/dlb: add port_unlink and port_unlinks_in_progress Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 23/27] event/dlb: add eventdev_start Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 24/27] event/dlb: add timeout_ticks, dump, xstats, and selftest Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 25/27] event/dlb: add enqueue and its burst variants Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 26/27] event/dlb: add dequeue, dequeue_burst, and variants Tim McDaniel
2020-06-27  4:37 ` [dpdk-dev] [PATCH 27/27] event/dlb: add eventdev_stop and eventdev_close Tim McDaniel
     [not found] <1593232671-5690-0-git-send-email-timothy.mcdaniel@intel.com>
2020-07-30 19:49 ` [dpdk-dev] [PATCH 00/27] Add Intel DLM PMD to 20.11 McDaniel, Timothy
2020-07-30 19:49   ` [dpdk-dev] [PATCH 01/27] eventdev: dlb upstream prerequisites McDaniel, Timothy
2020-08-11 17:44     ` Jerin Jacob
  -- strict thread matches above, loose matches on Subject: below --
2020-06-12 21:24 [dpdk-dev] [PATCH 00/27] V1 event/dlb add Intel DLB PMD McDaniel, Timothy
2020-06-12 21:24 ` [dpdk-dev] [PATCH 01/27] eventdev: dlb upstream prerequisites McDaniel, Timothy
2020-06-13  3:59   ` Jerin Jacob
2020-06-13 10:43     ` Mattias Rönnblom
2020-06-18 15:51       ` McDaniel, Timothy
2020-06-18 15:44     ` McDaniel, Timothy

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