Re: [PATCH v2 0/5] Dynamic HW Mempool Detection Support

[Olivier Matz <olivier.matz@6wind.com>]

On Mon, Jan 15, 2018 at 11:41:09AM +0530, Hemant Agrawal wrote:
> W.r.t the multiple discussions in the past about the ability to
> dynamically detect the HW mempool support. [1],[2] & [3]
> 
> This patchset helps in removing the current static mempool selection
> model and provides a flexible model to select the pktmbuf mempool
> in more dynamic way. 
> 
> 1) This patchset updates the hw mempool on the basis of device probe()),
>    thus avoiding the need to specify the hw mempool in config file and 
>    focing different binaries for diffirent config architectures.
> 2) Selection of mempool ops though --mbuf-pool-ops-name (cmd line arg)
>    which can overridden the scheme(1)
> 3) A new best mempool ops selection logic.
> 4) A new wrapper for the pktmbuf_pool_create helper to take mempool ops
>    name as an argument as well.
> 
> *Limitations and open points*
> 
> It was suggested to add all APIs in librte_mbuf, currently internal_config
> is storing the mempool_ops names. So internal_config is exported in this
> patchset. An alternate would be to keep these APIs in eal only and access
> them indirectly from librte_mbuf.

Instead of storing the mempool_ops name in internal config, can't it be
stored inside librte_mbuf? The eal code can call
rte_mbuf_set_user_mempool_ops(name) while parsing the arguments.

It has to be done carefully so that it works with secondary processes.


> Moreover, this logic can be further extended with addition for following
> patch, which is still under discussion:
> 
> The ethdev PMD capability exposed through existing
> rte_eth_dev_pool_ops_supported() to select the update the mempool ops with
> some "weight" based algorithm like:
> http://dpdk.org/dev/patchwork/patch/32245/
> 
> -----
> [1]Multiple Pktmbuf mempool support
> http://dpdk.org/ml/archives/dev/2017-September/076531.html
> [2]Allow application set mempool handle
> http://dpdk.org/ml/archives/dev/2017-June/067022.html
> Other discussions
> [3] http://dpdk.org/ml/archives/dev/2017-December/084775.html 
> ------
> Changes in v2:
> 1. Changed the active mempool to platform mempool
> 2. Moved all the relavant APIs to librte_mbuf 
> 3. Added pktmbuf_create_pool_specific wrapper in this patch series.
> 
> Hemant Agrawal (5):
>   eal: prefix mbuf pool ops name with user defined
>   eal: add platform mempool ops name in internal config
>   mbuf: support register mempool Hw ops name APIs
>   mbuf: pktmbuf pool create helper for specific mempool ops
>   mbuf: add user command line config mempools ops API
> 
>  doc/guides/rel_notes/deprecation.rst       |  7 +++
>  lib/librte_eal/bsdapp/eal/eal.c            |  4 +-
>  lib/librte_eal/common/eal_common_options.c |  3 +-
>  lib/librte_eal/common/eal_internal_cfg.h   |  5 ++-
>  lib/librte_eal/linuxapp/eal/eal.c          |  4 +-
>  lib/librte_eal/rte_eal_version.map         |  1 +
>  lib/librte_mbuf/Makefile                   |  1 +
>  lib/librte_mbuf/rte_mbuf.c                 | 67 ++++++++++++++++++++++++---
>  lib/librte_mbuf/rte_mbuf.h                 | 72 ++++++++++++++++++++++++++++++

I think the code to manage the user/platform mempool ops could
go in a separate file. What about rte_mbuf_pool_ops.[ch] ?