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From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v2 1/2] ethdev: add buffered tx api
Date: Wed, 9 Mar 2016 15:23:50 +0000	[thread overview]
Message-ID: <2601191342CEEE43887BDE71AB97725836B1A627@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <1964417.t7N6HDkJH0@xps13>

> 
> 2016-03-09 13:36, Ananyev, Konstantin:
> > > > +   if (to_send == 0)
> > > > +           return 0;
> > >
> > > Why this check is done in the lib?
> > > What is the performance gain if we are idle?
> > > It can be done outside if needed.
> >
> > Yes, that could be done outside, but if user has to do it anyway,
> > why not to put it inside?
> > I don't expect any performance gain/loss because of that -
> > just seems a bit more convenient to the user.
> 
> It is handling an idle case so there is no gain obviously.
> But the condition branching is surely a loss.

I suppose that condition should always be checked:
either in user code prior to function call or inside the
function call itself.
So don't expect any difference in performance here...
Do you have any particular example when you think it would? 
Or are you talking about rte_eth_tx_buffer() calling
rte_eth_tx_buffer_flush() internally?
For that one - both are flush is 'static inline' , so I expect
compiler be smart enough to remove this redundant check.  

> So why the user would you like to do this check?
Just for user convenience - to save him doing that manually.

Konstantin

  reply	other threads:[~2016-03-09 15:24 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-15 14:43 [dpdk-dev] [PATCH 0/2] add support for buffered tx to ethdev Tomasz Kulasek
2016-01-15 14:43 ` [dpdk-dev] [PATCH 1/2] ethdev: add buffered tx api Tomasz Kulasek
2016-01-15 18:13   ` Stephen Hemminger
2016-01-15 18:14   ` Stephen Hemminger
2016-01-15 18:44   ` Ananyev, Konstantin
2016-02-02 10:00     ` Kulasek, TomaszX
2016-02-02 13:49       ` Ananyev, Konstantin
2016-02-09 17:02         ` Kulasek, TomaszX
2016-02-09 23:56           ` Ananyev, Konstantin
2016-02-12 11:44             ` Ananyev, Konstantin
2016-02-12 16:40               ` Ivan Boule
2016-02-12 17:33                 ` Bruce Richardson
2016-01-15 14:43 ` [dpdk-dev] [PATCH 2/2] examples: sample apps rework to use " Tomasz Kulasek
2016-01-15 18:12 ` [dpdk-dev] [PATCH 0/2] add support for buffered tx to ethdev Stephen Hemminger
2016-02-24 17:08 ` [dpdk-dev] [PATCH v2 " Tomasz Kulasek
2016-02-24 17:08   ` [dpdk-dev] [PATCH v2 1/2] ethdev: add buffered tx api Tomasz Kulasek
2016-03-08 22:52     ` Thomas Monjalon
2016-03-09 13:36       ` Ananyev, Konstantin
2016-03-09 14:25         ` Thomas Monjalon
2016-03-09 15:23           ` Ananyev, Konstantin [this message]
2016-03-09 15:26             ` Thomas Monjalon
2016-03-09 15:32               ` Kulasek, TomaszX
2016-03-09 15:37                 ` Thomas Monjalon
2016-03-09 15:42               ` Ananyev, Konstantin
2016-03-09 15:52                 ` Thomas Monjalon
2016-03-09 16:17                   ` Ananyev, Konstantin
2016-03-09 16:21                     ` Thomas Monjalon
2016-03-09 16:35       ` Kulasek, TomaszX
2016-03-09 17:06         ` Thomas Monjalon
2016-03-09 18:12           ` Kulasek, TomaszX
2016-02-24 17:08   ` [dpdk-dev] [PATCH v2 2/2] examples: rework to use " Tomasz Kulasek
2016-02-25 16:17   ` [dpdk-dev] [PATCH v2 0/2] add support for buffered tx to ethdev Ananyev, Konstantin
2016-03-10 10:57   ` [dpdk-dev] [PATCH v3 " Tomasz Kulasek
2016-03-10 10:57     ` [dpdk-dev] [PATCH v3 1/2] ethdev: add buffered tx api Tomasz Kulasek
2016-03-10 16:23       ` Thomas Monjalon
2016-03-10 17:15         ` Kulasek, TomaszX
2016-03-10 10:57     ` [dpdk-dev] [PATCH v3 2/2] examples: rework to use buffered tx Tomasz Kulasek
2016-03-10 11:31     ` [dpdk-dev] [PATCH v3 0/2] add support for buffered tx to ethdev Ananyev, Konstantin
2016-03-10 16:01       ` Jastrzebski, MichalX K
2016-03-10 17:19     ` [dpdk-dev] [PATCH v4 " Tomasz Kulasek
2016-03-10 17:19       ` [dpdk-dev] [PATCH v4 1/2] ethdev: add buffered tx api Tomasz Kulasek
2016-03-10 17:19       ` [dpdk-dev] [PATCH v4 2/2] examples: rework to use buffered tx Tomasz Kulasek
2016-03-11 16:39       ` [dpdk-dev] [PATCH v4 0/2] add support for buffered tx to ethdev Thomas Monjalon

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