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From: "Kulasek, TomaszX" <tomaszx.kulasek@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.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 15:32:05 +0000	[thread overview]
Message-ID: <3042915272161B4EB253DA4D77EB373A14E6A842@IRSMSX102.ger.corp.intel.com> (raw)
In-Reply-To: <5916803.8PiAMBcxJt@xps13>



> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Wednesday, March 9, 2016 16:27
> To: Ananyev, Konstantin <konstantin.ananyev@intel.com>
> Cc: Kulasek, TomaszX <tomaszx.kulasek@intel.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2 1/2] ethdev: add buffered tx api
> 
> 2016-03-09 15:23, Ananyev, Konstantin:
> > >
> > > 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.
> 
> Probably I've missed something. If we remove this check, the function will
> do nothing, right? How is it changing the behaviour?

If we remove this check, function will try to send 0 packets and check condition for error. So we gain nothing with removing that.

Tomasz

  reply	other threads:[~2016-03-09 15:32 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
2016-03-09 15:26             ` Thomas Monjalon
2016-03-09 15:32               ` Kulasek, TomaszX [this message]
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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