From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Wu, Jingjing" <jingjing.wu@intel.com>
Cc: "Zhang, Helin" <helin.zhang@intel.com>,
"Mcnamara, John" <john.mcnamara@intel.com>,
dev@dpdk.org, ferruh.yigit@intel.com
Subject: Re: [dpdk-dev] i40e queues per VF
Date: Tue, 14 Mar 2017 10:31:28 +0100 [thread overview]
Message-ID: <3110305.l4UWzxzWQC@xps13> (raw)
In-Reply-To: <17951395.s0M76qHr7t@xps13>
ping again
2017-03-08 12:25, Thomas Monjalon:
> ping - still waiting for answers to below questions, please
>
> 2017-02-16 15:55, Thomas Monjalon:
> > 2017-02-16 13:58, Wu, Jingjing:
> > > From: Thomas Monjalon
> > > >
> > > > Hi,
> > > >
> > > > When reading the documentation, it is not easy to understand the capability of
> > > > i40evf for the number of queues.
> > > >
> > > > First, please could you explain why we need a build-time config option?
> > > > In the doc, there is neither justification nor tuning guidelines:
> > > >
> > > > http://dpdk.org/doc/guides/nics/i40e.html#config-file-options
> > > > "
> > > > CONFIG_RTE_LIBRTE_I40E_QUEUE_NUM_PER_PF (default 64) Number of
> > > > queues reserved for PF.
> > > > CONFIG_RTE_LIBRTE_I40E_QUEUE_NUM_PER_VF (default 4) Number of
> > > > queues reserved for each SR-IOV VF.
> > > > "
> > >
> > > This number is used as initialization time to allocate queue number
> > > for PF/VF for HW's queue pool. Will add more description in i40e.rst.
> >
> > The description "Number of queues reserved for each SR-IOV VF" seems
> > partially wrong. Please explain it is a queue pair.
> >
> > > > I feel these are hard limits and should be some constants in the code, not some
> > > > build configuration options.
> > > >
> > > > The other doc to look at is:
> > > > http://dpdk.org/doc/guides/nics/intel_vf.html#intel-fortville-10-40-gigabit-
> > > > ethernet-controller-vf-infrastructure
> > > > "
> > > > Each VF can have a maximum of 16 queue pairs.
> > > > "
> > > >
> > > > Do we agree that a queue pair is 1 Rx queue / 1 Tx queue?
> > > > Note: the concept of queue pairs in Intel VF should be explained somewhere.
> > > >
> > > Yes.
> > > > Below, a different limitation is given:
> > > > "
> > > > The available queue number(at most 4) per VF depends on the total number of
> > > > pool, which is determined by the max number of VF at PF initialization stage and
> > > > the number of queue specified in config "
> > > >
> > > I think there may be some inconsistent description in doc intel_vf.rst due to
> > > Multiple kinds of NICs. We should correct them.
> > > Thanks for pointing that.
> > >
> > > > So what is the real maximum of queue pairs? 4 or 16?
> > > > The datasheet talks about 16 queues. Is it 8 pairs?
> > >
> > > That's is 16 queue pairs. 16 RX queues and 16 Tx queues.
> > > >
> > > > Is there something to configure the number of queues when creating VF with the
> > > > kernel driver?
> > >
> > > In kernel driver, it seems at most only 4 queues are supported. That's
> > > Why we add build-time config option to make more queues are possible.
> >
> > If we can create 16 queue pairs, why restrict the default configuration to 4?
> > Why is it a build-time config option?
next prev parent reply other threads:[~2017-03-14 9:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 10:07 Thomas Monjalon
2017-02-16 10:03 ` Xu, Qian Q
2017-02-16 13:58 ` Wu, Jingjing
2017-02-16 14:55 ` Thomas Monjalon
2017-03-08 11:25 ` Thomas Monjalon
2017-03-14 9:31 ` Thomas Monjalon [this message]
2017-03-21 6:01 ` Wu, Jingjing
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