From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Kulasek, TomaszX" <tomaszx.kulasek@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2 1/2] ethdev: add buffered tx api
Date: Wed, 09 Mar 2016 16:37:21 +0100 [thread overview]
Message-ID: <7687094.ndhEsKzoZH@xps13> (raw)
In-Reply-To: <3042915272161B4EB253DA4D77EB373A14E6A842@IRSMSX102.ger.corp.intel.com>
2016-03-09 15:32, Kulasek, TomaszX:
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 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.
Actually I should not arguing why removing it,
but you should arguing why adding it :)
next prev parent reply other threads:[~2016-03-09 16:03 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
2016-03-09 15:37 ` Thomas Monjalon [this message]
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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