From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id CB0A3438F2; Thu, 18 Jan 2024 12:18:59 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 579C440DF5; Thu, 18 Jan 2024 12:18:59 +0100 (CET) Received: from inbox.dpdk.org (inbox.dpdk.org [95.142.172.178]) by mails.dpdk.org (Postfix) with ESMTP id 5115F402B5 for ; Thu, 18 Jan 2024 12:18:58 +0100 (CET) Received: by inbox.dpdk.org (Postfix, from userid 33) id 3BFA6438F3; Thu, 18 Jan 2024 12:18:58 +0100 (CET) From: bugzilla@dpdk.org To: dev@dpdk.org Subject: [Bug 1368] inconsistency in eventdev dev_info and config structs makes some valid configs impossible Date: Thu, 18 Jan 2024 11:18:58 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: DPDK X-Bugzilla-Component: eventdev X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: bruce.richardson@intel.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: Normal X-Bugzilla-Assigned-To: dev@dpdk.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Type: multipart/alternative; boundary=17055767380.47AdacB8.1948714 Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org --17055767380.47AdacB8.1948714 Date: Thu, 18 Jan 2024 12:18:58 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All https://bugs.dpdk.org/show_bug.cgi?id=3D1368 Bug ID: 1368 Summary: inconsistency in eventdev dev_info and config structs makes some valid configs impossible Product: DPDK Version: unspecified Hardware: All OS: All Status: UNCONFIRMED Severity: normal Priority: Normal Component: eventdev Assignee: dev@dpdk.org Reporter: bruce.richardson@intel.com Target Milestone: --- In the rte_event_dev_info struct[1], we have the max_event_queues[2] and max_single_link_event_port_queue_pairs[3] members. The doxygen docs on the latter states: "These ports and queues are not accounted for in max_event_ports or max_event_queues." This implies that a device which has 8 regular queues and an extra 8 single-link only queues, would report max_event_queues =3D=3D 8, and max_single_link_event_port_queue_pairs =3D=3D 8 on return from rte_event_dev_info_get() function. Those values returned from info_get are generally to be used to guide the configuration using rte_event_dev_configure() API, which takes the rte_event_dev_config[4] struct. This has two similar fields, in nb_event_queues[5] and nb_single_link_event_port_queues[6]. However, a problem arises in that the documentation states that nb_event_queues cannot be greater than the previously reported max_event_queues (which by itself makes sense), but the documentation also states that nb_single_link_event_port_queues is a subset of the overall event ports and queues, and cannot be greater than the nb_event_queues given in the same config structure. To illustrate the issue by continuing to use the same example as above, suppose an app wants to take that device with 8 regular queues and 8 single link ones, and have an app with 2 shared processing queues, e.g. for load-balancing packets/events among 8 cores, but also wants to use the 8 single link queues to allow sending packets/events directly to each core without load balancing. In this 2 + 8 scenario, there is no valid dev_config struct settings that will work: * making the 8 a subset of the nb_event_queues, means that nb_event_queues is 10, which is greater than max_event_queues and so invalid. * keeping them separate, so that nb_event_queues =3D=3D 2 and nb_single_link_port_queues =3D=3D 8 violates the constraint that the single_link value cannot exceed the former nb_event_queues value. We therefore need to adjust the constraints to make things work. Now we can do so, while keeping the single_link value *not included* in the total-count in dev_info, but have it *included* in the config struct, but such a setup is very confusing for the user. Therefore, I think instead we need to correct this by aligning the two structures - either the single_link queues are included in the queue/port counts in both structs, or they aren't included. [1] https://doc.dpdk.org/api/structrte__event__dev__info.html [2] https://doc.dpdk.org/api/structrte__event__dev__info.html#a1cebb1d19943d6b8= e3d6e51ffc72982a [3] https://doc.dpdk.org/api/structrte__event__dev__info.html#ae65bf9e4dba80ccb= 205f3c43f5907d5d [4] https://doc.dpdk.org/api/structrte__event__dev__config.html [5] https://doc.dpdk.org/api/structrte__event__dev__config.html#a703c026d74436b= 05fc656652324101e4 [6] https://doc.dpdk.org/api/structrte__event__dev__config.html#a39f29448dce5ba= f491f6685299faa0c9 --=20 You are receiving this mail because: You are the assignee for the bug.= --17055767380.47AdacB8.1948714 Date: Thu, 18 Jan 2024 12:18:58 +0100 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All
Bug ID 1368
Summary inconsistency in eventdev dev_info and config structs makes s= ome valid configs impossible
Product DPDK
Version unspecified
Hardware All
OS All
Status UNCONFIRMED
Severity normal
Priority Normal
Component eventdev
Assignee dev@dpdk.org
Reporter bruce.richardson@intel.com
Target Milestone --- 

In the rte_event_dev_info struct[1=
], we have the max_event_queues[2] and
max_single_link_event_port_queue_pairs[3] members. The doxygen docs on the
latter states: "These ports and queues are not accounted for in
max_event_ports or max_event_queues."

This implies that a device which has 8 regular queues and an extra 8
single-link only queues, would report max_event_queues =3D=3D 8, and
max_single_link_event_port_queue_pairs =3D=3D 8 on return from
rte_event_dev_info_get() function.

Those values returned from info_get are generally to be used to guide the
configuration using rte_event_dev_configure() API, which takes the
rte_event_dev_config[4] struct. This has two similar fields, in
nb_event_queues[5] and nb_single_link_event_port_queues[6]. However, a
problem arises in that the documentation states that nb_event_queues cannot
be greater than the previously reported max_event_queues (which by itself
makes sense), but the documentation also states that
nb_single_link_event_port_queues is a subset of the overall event ports and
queues, and cannot be greater than the nb_event_queues given in the same
config structure.

To illustrate the issue by continuing to use the same example as above,
suppose an app wants to take that device with 8 regular queues and 8 single
link ones, and have an app with 2 shared processing queues, e.g. for
load-balancing packets/events among 8 cores, but also wants to use the 8
single link queues to allow sending packets/events directly to each core
without load balancing.  In this 2 + 8 scenario, there is no valid
dev_config struct settings that will work:
* making the 8 a subset of the nb_event_queues, means that nb_event_queues
  is 10, which is greater than max_event_queues and so invalid.
* keeping them separate, so that nb_event_queues =3D=3D 2 and
  nb_single_link_port_queues =3D=3D 8 violates the constraint that the
  single_link value cannot exceed the former nb_event_queues value.

We therefore need to adjust the constraints to make things work. Now we can
do so, while keeping the single_link value *not included* in the
total-count in dev_info, but have it *included* in the config struct, but
such a setup is very confusing for the user. Therefore, I think instead we
need to correct this by aligning the two structures - either the
single_link queues are included in the queue/port counts in both structs,
or they aren't included.

[1] h=
ttps://doc.dpdk.org/api/structrte__event__dev__info.html
[2]
https://doc.dpdk.org/api/structrte__event__dev=
__info.html#a1cebb1d19943d6b8e3d6e51ffc72982a
[3]
https://doc.dpdk.org/api/structrte__event__dev=
__info.html#ae65bf9e4dba80ccb205f3c43f5907d5d
[4] https://doc.dpdk.org/api/structrte__event__dev__config.html
[5]
https://doc.dpdk.org/api/structrte__event__d=
ev__config.html#a703c026d74436b05fc656652324101e4
[6]
https://doc.dpdk.org/api/structrte__event__d=
ev__config.html#a39f29448dce5baf491f6685299faa0c9

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