patches for DPDK stable branches
 help / color / mirror / Atom feed
From: Thomas Monjalon <thomas@monjalon.net>
To: Matan Azrad <matan@mellanox.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	Raslan Darawsheh <rasland@mellanox.com>,
	Shiri Kuzin <shirik@mellanox.com>,
	"stable@dpdk.org" <stable@dpdk.org>,
	Shahaf Shuler <shahafs@mellanox.com>,
	Slava Ovsiienko <viacheslavo@mellanox.com>,
	Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [dpdk-stable] [PATCH] common/mlx5: fix CPU detection for PCI relaxed ordering
Date: Sun, 19 Jul 2020 13:13:09 +0200
Message-ID: <4865593.5jmsT3qBYc@thomas> (raw)
In-Reply-To: <DB3PR0502MB40284BD5A1EAF26762F4678DD27A0@DB3PR0502MB4028.eurprd05.prod.outlook.com>

19/07/2020 12:56, Matan Azrad:
> 
> From: Thomas Monjalon
> > The detection of the CPU was done in a constructor and shared in a global
> > variable.
> > 
> > This variable may not be visible in the net PMD because it was not exported
> > as part of the .map file.
> 
> Can you explain exactly when it is not visible?

I depends on linker options.

> > It is fixed by exporting a function, which is cleaner than a variable.
> 
> Can you explain why?
> We have classic example - rte_eth_devices.

There is more control and more abstraction in functions,
it can provide futre-proof abstraction.

We should not export variables at all,
it is a basic rule of writing API.
Having a bad example in ethdev doesn't mean we should follow it.

> > By checking the CPU only at the first call of the function, doing the check in a
> > constructor becomes useless.
> 
> Yes, but why not to do it in constructor? this variable is initialized only once and doesn't depend in any parameter.

Constructor must remain minimal.
If constructor can be avoided, it must be.
This is a golden rule.

> > Note: the priority of the constructor was probably irrelevant.

No comment about the constructor priority which was set as LOG
for no good reason, proving that this code was not well reviewed?

> > At the same time, the comments are reworded or dropped if useless.
> > 
> > Fixes: 4c204fe5e5d2 ("common/mlx5: disable relaxed ordering in unsuitable
> > CPUs")
> > Cc: shirik@mellanox.com
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>




  reply	other threads:[~2020-07-19 11:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-19 10:07 Thomas Monjalon
2020-07-19 10:11 ` Slava Ovsiienko
2020-07-19 10:56 ` Matan Azrad
2020-07-19 11:13   ` Thomas Monjalon [this message]
2020-07-19 11:41     ` Matan Azrad
2020-07-19 13:33       ` Thomas Monjalon
2020-07-24 15:43         ` Matan Azrad
2020-07-28 10:21           ` Thomas Monjalon
2020-07-28 10:38             ` Matan Azrad
2020-07-24 14:53 ` [dpdk-stable] [dpdk-dev] " David Marchand

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=4865593.5jmsT3qBYc@thomas \
    --to=thomas@monjalon.net \
    --cc=dev@dpdk.org \
    --cc=matan@mellanox.com \
    --cc=mdr@ashroe.eu \
    --cc=nhorman@tuxdriver.com \
    --cc=rasland@mellanox.com \
    --cc=shahafs@mellanox.com \
    --cc=shirik@mellanox.com \
    --cc=stable@dpdk.org \
    --cc=viacheslavo@mellanox.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

patches for DPDK stable branches

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/stable/0 stable/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 stable stable/ https://inbox.dpdk.org/stable \
		stable@dpdk.org
	public-inbox-index stable

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.stable


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git