Re: [dpdk-dev] [PATCH 0/7] Patches to split architecture specific operations from DPDK

[David Marchand <david.marchand@6wind.com>]

Hello Chao,

On Fri, Sep 26, 2014 at 11:33 AM, Chao Zhu <bjzhuc@cn.ibm.com> wrote:

> The set of patches split x86 architecture specific operations from DPDK
> and put them to the
> arch directories of i686 and x86_64 architecture. This will make the
> adpotion of DPDK much easier
> on other computer architecture. For a new architecture, just add an
> architecture specific
> directory and necessary building configuration files, then DPDK can
> support it.
>
>
Here is a different approach for the headers splitting.

If we are going to support multiple architectures, the best would be to
have a specific header for each arch which implements a common API (no need
for any _arch suffix).
These headers would be located in lib/librte_eal/common/include/arch/$arch/
rather than lib/librte_eal/common/include/$arch/arch/ (which looks odd to
me).
Makefiles can add some -I for dpdk to build itself (and we can remove those
symlinks from the makefiles).
Makefiles only install the specific headers in RTE_SDK/include for use by
applications.

For common code and documentation, we can add a "generic" directory in
lib/librte_eal/common/include (or "arch-generic", or "shared" ... any
better idea ?).
DPDK makefiles installs the generic headers in RTE_SDK/include/generic.
arch headers (like rte_atomic.h) include the generic one
(<generic/rte_atomic.h>).

These generic headers can be implemented using compiler intrinsics when
possible.
They also include the doxygen stuff in a single place.


This would look like something like this, for rte_atomic.h :
- in DPDK sources
$ ls lib/librte_eal/common/include/*/rte_atomic.h
lib/librte_eal/common/include/i686/rte_atomic.h
lib/librte_eal/common/include/x86_64/rte_atomic.h
lib/librte_eal/common/include/generic/rte_atomic.h

- in installed RTE_SDK
$ ls RTE_SDK/include/{,*/}rte_atomic.h
RTE_SDK/include/rte_atomic.h
RTE_SDK/include/generic/rte_atomic.h

Comments ?


I am only focusing on the first patchset at the moment, but if we can find
consensus here, a respin of the two patchsets would be great.

Thanks.

-- 
David Marchand