[ovs-dev] [PATCH v2] INSTALL.DPDK: Update details of XL710 restrictions for DPDK 2.2.

Stokes, Ian ian.stokes at intel.com
Tue Feb 16 11:31:32 UTC 2016



> -----Original Message-----
> From: Flavio Leitner [mailto:fbl at sysclose.org]
> Sent: Friday, February 12, 2016 1:37 AM
> To: Stokes, Ian
> Cc: dev at openvswitch.org
> Subject: Re: [ovs-dev] [PATCH v2] INSTALL.DPDK: Update details of XL710
> restrictions for DPDK 2.2.
> 
> On Tue,  9 Feb 2016 14:48:47 +0000
> Ian Stokes <ian.stokes at intel.com> wrote:
> 
> > DPDK 2.2 removes restrictions related to maximum number of TX queues
> > for XL710 devices. Update documentation to reflect these changes.
> >
> > Signed-off-by: Ian Stokes <ian.stokes at intel.com>
> > ---
> >  INSTALL.DPDK.md |   22 +++++++++++-----------
> >  1 files changed, 11 insertions(+), 11 deletions(-)
> >
> > diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md index d892788..b0659c9
> > 100644
> > --- a/INSTALL.DPDK.md
> > +++ b/INSTALL.DPDK.md
> > @@ -898,17 +898,17 @@ Restrictions:
> >      this with smaller page sizes.
> >
> >    Platform and Network Interface:
> > -  - Currently it is not possible to use an Intel XL710 Network
> Interface as a
> > -    DPDK port type on a platform with more than 64 logical cores.
> This is
> > -    related to how DPDK reports the number of TX queues that may be
> used by
> > -    a DPDK application with an XL710. The maximum number of TX queues
> supported
> > -    by a DPDK application for an XL710 is 64. If a user attempts to
> add an
> > -    XL710 interface as a DPDK port type to a system as described
> above the
> > -    port addition will fail as OVS will attempt to initialize a TX
> queue greater
> > -    than 64. This issue is expected to be resolved in a future DPDK
> release.
> > -    As a workaround a user can disable hyper-threading to reduce the
> overall
> > -    core count of the system to be less than or equal to 64 when
> using an XL710
> > -    interface with DPDK.
> > +  - By default with DPDK 2.2, a maximum of 64 TX queues can be used
> with an
> > +    Intel XL710 Network Interface on a platform with more than 64
> logical
> > +    cores. If a user attempts to add an XL710 interface as a DPDK
> port type to
> > +    a system as described above, an error will be reported that
> initialization
> > +    failed for the 65th queue. OVS will then roll back to the
> previous
> > +    successful queue initialization and use that value as the total
> number of
> > +    TX queues available with queue locking. If a user wishes to use
> more than
> > +    64 queues and avoid locking, then the
> > +    `CONFIG_RTE_LIBRTE_I40E_QUEUE_NUM_PER_PF` config parameter in
> DPDK must be
> > +    increased to the desired number of queues. Both DPDK and OVS must
> be
> > +    recompiled for this change to take effect.
> >
> >    vHost and QEMU v2.4.0+:
> >    - For versions of QEMU v2.4.0 and later, it is currently not
> > possible to
> 
> Could you please keep a changelog section after the diffstat?
> It would help to understand what has changed since the initial proposal.
> 
Thanks for the review Flavio, I'll keep a change log going forward. Apologies for not including one before.

> Based on current dpdk_eth_dev_queue_setup() and dpdk commit
> 705b57f82054431ed681cc899129e7c70fb36138 (i40e: enlarge the number of
> supported queues)
> 
The line above, do you want this added to the patch or is it an instruction for the change log?

> Acked-by: Flavio Leitner <fbl at sysclose.org>
> 
> Also needs to go in branch-2.5.
> 
> --
> fbl




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