From: "Rao, Nikhil" <nikhil.rao@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>,
"Singh, Jasvinder" <jasvinder.singh@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] ethdev: support double precision RED queue weight
Date: Thu, 10 Jan 2019 06:23:16 +0000 [thread overview]
Message-ID: <1F668163772FA946975B9466A9DFF729EDDA4F7C@ORSMSX122.amr.corp.intel.com> (raw)
In-Reply-To: <20181210080109.617902f1@xeon-e3>
> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Monday, December 10, 2018 9:31 PM
Hi Stephen,
> To: Rao, Nikhil <nikhil.rao@intel.com>
> Cc: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; Singh, Jasvinder
> <jasvinder.singh@intel.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] ethdev: support double precision RED queue
> weight
>
> On Mon, 10 Dec 2018 05:43:37 +0000
> "Rao, Nikhil" <nikhil.rao@intel.com> wrote:
>
> > > -----Original Message-----
> > > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > > Sent: Thursday, November 29, 2018 11:43 AM
> > > To: Rao, Nikhil <nikhil.rao@intel.com>
> > > Cc: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; Singh,
> > > Jasvinder <jasvinder.singh@intel.com>; dev@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH] ethdev: support double precision RED
> > > queue weight
> > >
> > > On Thu, 29 Nov 2018 11:24:42 +0530
> > > Nikhil Rao <nikhil.rao@intel.com> wrote:
> > >
> > > > RED queue weight is currently specified as a negated log of 2.
> > > >
> > > > Add support for RED queue weight to be specified in double
> > > > precision and TM capability flags for double precision and negated
> > > > log2 RED queue weight support.
> > > >
> > > > Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
> > >
> > > Since this is an ABI break anyway, why not just commit to the new format?
> >
> > Hi Stephen,
> >
> > Can you please provide more detail on your comment ? are you suggesting
> replacing the wq_log2/wq_dp with a double ?
> >
> > Thanks,
> > Nikhil
>
>
> My comment is that since you are changing a structure layout, which would
> break existing users; why not go farther and just fix the API to a better
> version. I don't think any projects use this code anyway, see my talk
> (https://github.com/shemminger/dpdk-metrics).
Sorry for the delay. I don't get your reference to a better version, the structure supports both formats using a union,
similar to how it's done in other DPDK APIs (struct rte_crypto_sym_xform for example). If you have a suggestion for a better layout,
please let me know.
>
> Isn't floating point going to be expensive. Or is it only during the setup
> process, not enqueue/dequeue.
Yes, floating point may end up to be more expensive (and the RED computation is invoked at every enqueue)
Nikhil
next prev parent reply other threads:[~2019-01-10 6:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 5:54 Nikhil Rao
2018-11-29 6:12 ` Stephen Hemminger
2018-12-10 5:43 ` Rao, Nikhil
2018-12-10 16:01 ` Stephen Hemminger
2019-01-10 6:23 ` Rao, Nikhil [this message]
2018-12-10 15:57 ` Stephen Hemminger
2019-01-07 16:39 ` Dumitrescu, Cristian
2019-01-10 16:35 ` [dpdk-dev] [PATCH v2] " Nikhil Rao
2019-03-29 20:16 ` Dumitrescu, Cristian
2019-03-29 20:16 ` Dumitrescu, Cristian
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