Re: [dpdk-stable] [19.11 4/4] crypto/qat: add minimum enq threshold

["Trahe, Fiona" <fiona.trahe@intel.com>]

Thanks Luca

> -----Original Message-----
> From: Luca Boccassi <bluca@debian.org>
> Sent: Friday, August 7, 2020 3:53 PM
> To: Kusztal, ArkadiuszX <arkadiuszx.kusztal@intel.com>; Trahe, Fiona <fiona.trahe@intel.com>
> Cc: stable@dpdk.org
> Subject: Re: [dpdk-stable] [19.11 4/4] crypto/qat: add minimum enq threshold
> 
> On Fri, 2020-08-07 at 14:57 +0200, Arek Kusztal wrote:
> > [ upstream commit 47c3f7a41a26c9943f9804691d03828b2ce09f40 ]
> >
> > This patch adds minimum enqueue threshold to Intel
> > QuickAssist Technology PMD.
> > It is an optimisation, configured by a command line option,
> > which can be used to reduce MMIO write occurrences.
> >
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
> > Signed-off-by: Arek Kusztal <arkadiuszx.kusztal@intel.com>
> > ---
> >  doc/guides/cryptodevs/qat.rst       | 18 +++++++
> >  drivers/common/qat/qat_common.c     |  3 ++
> >  drivers/common/qat/qat_common.h     |  3 ++
> >  drivers/common/qat/qat_device.c     | 99 ++++++++++++++++++++++++++++++++-----
> >  drivers/common/qat/qat_device.h     | 22 +++++++--
> >  drivers/common/qat/qat_qp.c         | 10 ++++
> >  drivers/common/qat/qat_qp.h         |  3 ++
> >  drivers/compress/qat/qat_comp_pmd.c | 14 +++++-
> >  drivers/compress/qat/qat_comp_pmd.h |  4 +-
> >  drivers/crypto/qat/qat_asym_pmd.c   | 14 +++++-
> >  drivers/crypto/qat/qat_asym_pmd.h   |  4 +-
> >  drivers/crypto/qat/qat_sym_pmd.c    | 14 +++++-
> >  drivers/crypto/qat/qat_sym_pmd.h    |  4 +-
> >  13 files changed, 190 insertions(+), 22 deletions(-)
> >
> > diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
> > index 5135703..aa3cdcf 100644
> > --- a/doc/guides/cryptodevs/qat.rst
> > +++ b/doc/guides/cryptodevs/qat.rst
> > @@ -273,6 +273,24 @@ allocated while for GEN1 devices, 12 buffers are allocated, plus 1472 bytes
> over
> >  	larger than the input size).
> >
> >
> > +Running QAT PMD with minimum threshold for burst size
> > +~~~~~~~~~~~~~~~~~~~~~~~~
> > +
> > +If only a small number or packets can be enqueued. Each enqueue causes an expensive MMIO write.
> > +These MMIO write occurrences can be optimised by setting any of the following parameters
> > +- qat_sym_enq_threshold
> > +- qat_asym_enq_threshold
> > +- qat_comp_enq_threshold
> > +When any of these parameters is set rte_cryptodev_enqueue_burst function will
> > +return 0 (thereby avoiding an MMIO) if the device is congested and number of packets
> > +possible to enqueue is smaller.
> > +To use this feature the user must set the parameter on process start as a device additional parameter:
> > + .example: '-w 03:01.1,qat_sym_enq_threshold=32,qat_comp_enq_threshold=16'
> > +All parameters can be used with the same device regardless of order. Parameters are separated
> > +by comma. When the same parameter is used more than once first occurrence of the parameter
> > +is used.
> > +Maximum threshold that can be set is 32.
> > +
> >  Device and driver naming
> >  ~~~~~~~~~~~~~~~~~~~~~~~
> 
> Normally I wouldn't accept a patch that adds new command line features,
> but given it's restricted to a single PMD _and_ the feature is present
> in the first short term release after 19.11 (20.02) thus allowing non-
> breaking upgrades, I'll merge the series.
> 
> --
> Kind regards,
> Luca Boccassi