From: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
To: Vinicius Costa Gomes <vinicius.gomes@intel.com>,
Cong Wang <xiyou.wangcong@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
intel-wired-lan <intel-wired-lan@lists.osuosl.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
andre.guedes@intel.com, ivan.briano@intel.com,
boon.leong.ong@intel.com, richardcochran@gmail.com,
henrik@austad.us
Subject: Re: [next-queue PATCH 2/3] net/sched: Introduce Credit Based Shaper (CBS) qdisc
Date: Wed, 27 Sep 2017 15:57:24 -0700 [thread overview]
Message-ID: <4b0e1610-c9df-191d-496e-4be04c785d2f@intel.com> (raw)
In-Reply-To: <87lgkzg7xv.fsf@intel.com>
Hi,
On 09/27/2017 02:14 PM, Vinicius Costa Gomes wrote:
> Hi,
>
> Cong Wang <xiyou.wangcong@gmail.com> writes:
>
>> On Tue, Sep 26, 2017 at 4:39 PM, Vinicius Costa Gomes
>> <vinicius.gomes@intel.com> wrote:
>>> +static int cbs_init(struct Qdisc *sch, struct nlattr *opt)
>>> +{
>>> + struct cbs_sched_data *q = qdisc_priv(sch);
>>> + struct net_device *dev = qdisc_dev(sch);
>>> +
>>> + if (!opt)
>>> + return -EINVAL;
>>> +
>>> + /* FIXME: this means that we can only install this qdisc
>>> + * "under" mqprio. Do we need a more generic way to retrieve
>>> + * the queue, or do we pass the netdev_queue to the driver?
>>> + */
>>> + q->queue = TC_H_MIN(sch->parent) - 1 - netdev_get_num_tc(dev);
>>> +
>>> + return cbs_change(sch, opt);
>>> +}
>>
>> Yeah it is ugly to assume its parent is mqprio, at least you should
>> error out if it is not the case.
>
> Will add an error for this, for now.
>
>>
>> I am not sure how we can solve this elegantly, perhaps you should
>> extend mqprio rather than add a new one?
>
> Is the alternative hinted in the FIXME worse? Instead of passing the
> index of the hardware queue to the driver we pass the pointer to a
> netdev_queue to the driver and it "discovers" the HW queue from that.
What if we keep passing the index, but calculate it from the netdev_queue
pointer instead?
i.e.: q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
At least it wouldn't rely on the root qdisc being of any specific type.
Regards,
Jesus
WARNING: multiple messages have this Message-ID (diff)
From: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
To: intel-wired-lan@osuosl.org
Subject: [Intel-wired-lan] [next-queue PATCH 2/3] net/sched: Introduce Credit Based Shaper (CBS) qdisc
Date: Wed, 27 Sep 2017 15:57:24 -0700 [thread overview]
Message-ID: <4b0e1610-c9df-191d-496e-4be04c785d2f@intel.com> (raw)
In-Reply-To: <87lgkzg7xv.fsf@intel.com>
Hi,
On 09/27/2017 02:14 PM, Vinicius Costa Gomes wrote:
> Hi,
>
> Cong Wang <xiyou.wangcong@gmail.com> writes:
>
>> On Tue, Sep 26, 2017 at 4:39 PM, Vinicius Costa Gomes
>> <vinicius.gomes@intel.com> wrote:
>>> +static int cbs_init(struct Qdisc *sch, struct nlattr *opt)
>>> +{
>>> + struct cbs_sched_data *q = qdisc_priv(sch);
>>> + struct net_device *dev = qdisc_dev(sch);
>>> +
>>> + if (!opt)
>>> + return -EINVAL;
>>> +
>>> + /* FIXME: this means that we can only install this qdisc
>>> + * "under" mqprio. Do we need a more generic way to retrieve
>>> + * the queue, or do we pass the netdev_queue to the driver?
>>> + */
>>> + q->queue = TC_H_MIN(sch->parent) - 1 - netdev_get_num_tc(dev);
>>> +
>>> + return cbs_change(sch, opt);
>>> +}
>>
>> Yeah it is ugly to assume its parent is mqprio, at least you should
>> error out if it is not the case.
>
> Will add an error for this, for now.
>
>>
>> I am not sure how we can solve this elegantly, perhaps you should
>> extend mqprio rather than add a new one?
>
> Is the alternative hinted in the FIXME worse? Instead of passing the
> index of the hardware queue to the driver we pass the pointer to a
> netdev_queue to the driver and it "discovers" the HW queue from that.
What if we keep passing the index, but calculate it from the netdev_queue
pointer instead?
i.e.: q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
At least it wouldn't rely on the root qdisc being of any specific type.
Regards,
Jesus
next prev parent reply other threads:[~2017-09-27 23:04 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-26 23:39 [next-queue PATCH 0/3] TSN: Add qdisc based config interface for CBS Vinicius Costa Gomes
2017-09-26 23:39 ` [Intel-wired-lan] " Vinicius Costa Gomes
2017-09-26 23:39 ` [next-queue PATCH 1/3] net/sched: Introduce the user API for the CBS shaper Vinicius Costa Gomes
2017-09-26 23:39 ` [Intel-wired-lan] " Vinicius Costa Gomes
2017-09-26 23:39 ` [next-queue PATCH 2/3] net/sched: Introduce Credit Based Shaper (CBS) qdisc Vinicius Costa Gomes
2017-09-26 23:39 ` [Intel-wired-lan] " Vinicius Costa Gomes
2017-09-27 20:23 ` Cong Wang
2017-09-27 20:23 ` [Intel-wired-lan] " Cong Wang
2017-09-27 21:14 ` Vinicius Costa Gomes
2017-09-27 21:14 ` [Intel-wired-lan] " Vinicius Costa Gomes
2017-09-27 22:57 ` Jesus Sanchez-Palencia [this message]
2017-09-27 22:57 ` Jesus Sanchez-Palencia
2017-09-27 23:11 ` Guedes, Andre
2017-09-27 23:11 ` [Intel-wired-lan] " Guedes, Andre
2017-09-28 22:34 ` Cong Wang
2017-09-28 22:34 ` [Intel-wired-lan] " Cong Wang
2017-09-28 23:07 ` Vinicius Costa Gomes
2017-09-28 23:07 ` [Intel-wired-lan] " Vinicius Costa Gomes
2017-09-26 23:39 ` [next-queue PATCH 3/3] igb: Add support for CBS offload Vinicius Costa Gomes
2017-09-26 23:39 ` [Intel-wired-lan] " Vinicius Costa Gomes
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