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From: Bruce Richardson <bruce.richardson@intel.com>
To: "Min Hu (Connor)" <humin29@huawei.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
	dev@dpdk.org, stable@dpdk.org,
	Thomas Monjalon <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>,
	Ciara Power <ciara.power@intel.com>,
	Keith Wiles <keith.wiles@intel.com>,
	Beilei Xing <beilei.xing@intel.com>, Jeff Guo <jia.guo@intel.com>,
	Haiyue Wang <haiyue.wang@intel.com>,
	Ajit Khaparde <ajit.khaparde@broadcom.com>,
	somnath.kotur@broadcom.com, qiming.yang@intel.com,
	qi.z.zhang@intel.com
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] ethdev: avoid blocking telemetry callback for link status
Date: Tue, 19 Jan 2021 10:06:02 +0000	[thread overview]
Message-ID: <20210119100602.GB1786@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <52dbf960-6d9e-5070-cde1-27c5a1e32e97@huawei.com>

On Tue, Jan 19, 2021 at 10:58:42AM +0800, Min Hu (Connor) wrote:
> Thank Stephen,
> but in which the scenarios, it should wait link to up, in which
> scenarios, it should not ?
> By the way, how to define the "wait" time value ?
> 

I believe the documentation somewhere refers to a wait time of up to 9
seconds, but I don't think it's terribly well defined. Some Intel NICs will
stall for a few seconds if the link is not yet stable or if the link
is down. With the link up, I don't think any NIC fails to return
immediately.
However, if delays in the app are something you want to avoid, the _nowait
varient is the one to call to be sure.

/Bruce

> 
> 
> 在 2021/1/19 10:26, Stephen Hemminger 写道:
> > On Tue, 19 Jan 2021 09:06:48 +0800
> > "Min Hu (Connor)" <humin29@huawei.com> wrote:
> > 
> > > Hi, Bruce and all,
> > > 	Do you know the difference between "rte_eth_link_get" and
> > > "rte_eth_link_get_nowait"? I know they call funciton "link_update"
> > > with differenct parameter "wait_to_complete"(set 1 means wait, set 0
> > >    means not wait). But how to define the "wait" time, and why it shoud wait?
> > > 	On the further, What are the application scenarios of the two
> > > APIs?
> > > 
> > 
> > The default behavior of rte_eth_link_get (in some drivers) is to wait
> > for link to come up.  Many drivers don't do this. It seems mostly the
> > Intel ones that do.
> > .
> > 

      reply	other threads:[~2021-01-19 10:06 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 12:17 [dpdk-stable] " Bruce Richardson
2021-01-14 15:06 ` Power, Ciara
2021-01-18 14:02   ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2021-01-18 14:48     ` Ferruh Yigit
2021-01-19  1:06 ` Min Hu (Connor)
2021-01-19  2:26   ` Stephen Hemminger
2021-01-19  2:58     ` Min Hu (Connor)
2021-01-19 10:06       ` Bruce Richardson [this message]

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