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From: Olivier Matz <olivier.matz@6wind.com>
To: Billy McFall <bmcfall@redhat.com>
Cc: thomas.monjalon@6wind.com, wenzhuo.lu@intel.com, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v6 1/3] ethdev: new API to free consumed buffers in Tx ring
Date: Wed, 15 Mar 2017 11:29:08 +0100	[thread overview]
Message-ID: <20170315112908.15b4c811@platinum> (raw)
In-Reply-To: <20170309205119.28170-2-bmcfall@redhat.com>

Hi Billy,

On Thu,  9 Mar 2017 15:51:17 -0500, Billy McFall <bmcfall@redhat.com> wrote:
> Add a new API to force free consumed buffers on Tx ring. API will return
> the number of packets freed (0-n) or error code if feature not supported
> (-ENOTSUP) or input invalid (-ENODEV).
> 
> Please double check my python coding in conf.py and make sure I
> implemented 'feature_str_len' properly.
> 
> Signed-off-by: Billy McFall <bmcfall@redhat.com>

[...]

> diff --git a/doc/guides/prog_guide/mempool_lib.rst b/doc/guides/prog_guide/mempool_lib.rst
> index ffdc109..a117881 100644
> --- a/doc/guides/prog_guide/mempool_lib.rst
> +++ b/doc/guides/prog_guide/mempool_lib.rst
> @@ -132,6 +132,32 @@ These user-owned caches can be explicitly passed to ``rte_mempool_generic_put()`
>  The ``rte_mempool_default_cache()`` call returns the default internal cache if any.
>  In contrast to the default caches, user-owned caches can be used by non-EAL threads too.
>  
> +In addition to a core's local cache, many of the drivers don't release the mbuf back to the mempool, or local cache,
> +immediately after the packet has been transmitted.
> +Instead, they leave the mbuf in their Tx ring and either perform a bulk release when the ``tx_rs_thresh`` has been
> +crossed or free the mbuf when a slot in the Tx ring is needed.
> +
> +An application can request the driver to release used mbufs with the ``rte_eth_tx_done_cleanup()`` API.
> +This API requests the driver to release mbufs that are no longer in use, independent of whether or not the
> +``tx_rs_thresh`` has been crossed.
> +There are two scenarios when an application may want the mbuf released immediately:
> +
> +* When a given packet needs to be sent to multiple destination interfaces (either for Layer 2 flooding or Layer 3
> +  multi-cast).
> +  One option is to make a copy of the packet or a copy of the header portion that needs to be manipulated.
> +  A second option is to transmit the packet and then poll the ``rte_eth_tx_done_cleanup()`` API until the reference
> +  count on the packet is decremented.
> +  Then the same packet can be transmitted to the next destination interface.
> +
> +* If an application is designed to make multiple runs, like a packet generator, and one run has completed.
> +  The application may want to reset to a clean state.
> +  In this case, it may want to call the ``rte_eth_tx_done_cleanup()`` API to request each destination interface it has
> +  been using to release all of its used mbufs.
> +
> +To determine if a driver supports this API, check for the *Free Tx mbuf on demand* feature in the *Network Interface
> +Controller Drivers* document.

I'm not sure the mempool documentation is the proper place to document
this API. I'll suggest to move it in ethdev documentation (poll_mode_drv.rst).

You can keep a small paragraph in mempool lib, but keep in mind that
mempool is not necessarily a pool of mbuf (it can be any kind of object).


Thanks,
Olivier

  reply	other threads:[~2017-03-15 10:29 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-20 16:01 [dpdk-dev] [PATCH v3 0/3] " Billy McFall
2017-01-20 16:01 ` [dpdk-dev] [PATCH v3 1/3] ethdev: " Billy McFall
2017-01-20 16:01 ` [dpdk-dev] [PATCH v3 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-01-22  3:47   ` Lu, Wenzhuo
2017-01-23 13:49     ` Billy McFall
2017-01-24  0:42       ` Lu, Wenzhuo
2017-01-20 16:01 ` [dpdk-dev] [PATCH v3 3/3] net/vhost: vHost " Billy McFall
2017-01-23 15:25 ` [dpdk-dev] [PATCH v3 0/3] new API to free consumed buffers in Tx ring Thomas Monjalon
2017-01-23 21:13 ` [dpdk-dev] [PATCH v4 " Billy McFall
2017-01-23 21:13   ` [dpdk-dev] [PATCH v4 1/3] ethdev: " Billy McFall
2017-01-23 21:13   ` [dpdk-dev] [PATCH v4 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-01-23 21:13   ` [dpdk-dev] [PATCH v4 3/3] net/vhost: vHost " Billy McFall
2017-01-27 18:37   ` [dpdk-dev] [PATCH v5 0/3] new API to free consumed buffers in Tx ring Billy McFall
2017-01-27 18:37     ` [dpdk-dev] [PATCH v5 1/3] ethdev: " Billy McFall
2017-02-27 13:48       ` Thomas Monjalon
2017-03-07 14:29         ` Billy McFall
2017-03-07 16:03           ` Thomas Monjalon
2017-03-09 15:49             ` Billy McFall
2017-03-09 17:11               ` Thomas Monjalon
2017-03-07 16:35           ` Mcnamara, John
2017-03-07 16:42       ` Mcnamara, John
2017-01-27 18:37     ` [dpdk-dev] [PATCH v5 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-02-27 13:49       ` Thomas Monjalon
2017-02-28  1:07       ` Lu, Wenzhuo
2017-01-27 18:38     ` [dpdk-dev] [PATCH v5 3/3] net/vhost: vHost " Billy McFall
2017-02-27 13:50       ` Thomas Monjalon
2017-02-28  6:41         ` Yuanhan Liu
2017-03-01 10:15           ` Maxime Coquelin
2017-03-07 21:59     ` [dpdk-dev] [PATCH v5 0/3] new API to free consumed buffers in Tx ring Thomas Monjalon
2017-03-09 20:51     ` [dpdk-dev] [PATCH v6 " Billy McFall
2017-03-09 20:51       ` [dpdk-dev] [PATCH v6 1/3] ethdev: " Billy McFall
2017-03-15 10:29         ` Olivier Matz [this message]
2017-03-15 15:01           ` Billy McFall
2017-03-15 10:30         ` Thomas Monjalon
2017-03-09 20:51       ` [dpdk-dev] [PATCH v6 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-03-13  3:17         ` Lu, Wenzhuo
2017-03-09 20:51       ` [dpdk-dev] [PATCH v6 3/3] net/vhost: vHost " Billy McFall
2017-03-15 10:27         ` Thomas Monjalon
2017-03-15 18:02       ` [dpdk-dev] [PATCH v7 0/3] new API to free consumed buffers in Tx ring Billy McFall
2017-03-15 18:02         ` [dpdk-dev] [PATCH v7 1/3] ethdev: " Billy McFall
2017-03-23 10:37           ` Olivier MATZ
2017-03-23 13:32             ` Billy McFall
2017-03-24 12:46               ` Olivier Matz
2017-03-24 13:18                 ` Billy McFall
2017-03-24 13:30                   ` Olivier Matz
2017-03-15 18:02         ` [dpdk-dev] [PATCH v7 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-03-15 18:02         ` [dpdk-dev] [PATCH v7 3/3] net/vhost: vHost " Billy McFall
2017-03-15 20:25         ` [dpdk-dev] [PATCH v7 0/3] new API to free consumed buffers in Tx ring Wiles, Keith
2017-03-24 18:55         ` [dpdk-dev] [PATCH v8 " Billy McFall
2017-03-24 18:55           ` [dpdk-dev] [PATCH v8 1/3] ethdev: " Billy McFall
2017-03-24 18:55           ` [dpdk-dev] [PATCH v8 2/3] net/e1000: e1000 igb support to free consumed buffers Billy McFall
2017-03-24 18:55           ` [dpdk-dev] [PATCH v8 3/3] net/vhost: vHost " Billy McFall
2017-03-27 15:20           ` [dpdk-dev] [PATCH v8 0/3] new API to free consumed buffers in Tx ring Thomas Monjalon
2017-04-19 16:25           ` Ferruh Yigit

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