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From: Neil Horman <nhorman@tuxdriver.com>
To: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Cc: dev@dpdk.org, Bruce Richardson <bruce.richardson@intel.com>,
	Thomas Monjalon <thomas@monjalon.net>,
	robin.jarry@6wind.com
Subject: Re: [dpdk-dev] [RFC PATCH 0/2] pmdinfogen: rewrite in Python
Date: Mon, 22 Jun 2020 08:41:17 -0400
Message-ID: <20200622124117.GA216823@hmswarspite.think-freely.org> (raw)
In-Reply-To: <20200622004503.29036-1-dmitry.kozliuk@gmail.com>

On Mon, Jun 22, 2020 at 03:45:01AM +0300, Dmitry Kozlyuk wrote:
> This is a PoC rewrite of pmdinfogen in Python with missing bits
> described below and in commits. Community input is desired.
> 
> Pros:
> 
> 1. Simpler build process without host apps.
> 2. Less build requirements (host libelf).
> 3. Easier debugging and maintenance with a high-level language.
> 4. Easier porting on Windows (only add new object format).
> 
Front matter: It seems reasonable to me to implement this in python, just for
ease of maintenence.

> Cons:
> 
> 1. No standard ELF or COFF module for Python
>     (amount of Python code without libelf on par with C code using it).
Thats not really true, pyelftools is pretty widely used, and packaged for
most(all) major distributions.  Requiring this kicks the can for (2) above down
the road a bit, but I would prefer to see that used rather than a custom
implementation, just to reduce the maint. burden

> 2. struct rte_pci_id must be synchronized with header file
>     (it's a few lines that never change).
> 
I think you can just use ctypes and the native python C interface to just import
the rte_pci_id structure from the native dpdk header to avoid this, no?

> There are no built-in or widely used Python libraries for ELF or COFF.
> Some ELF-parsing libraries exist on PyPI, but they're not very handy for
> the task and their installation would complicate build requirements.
> Thus, elf.py implements its own parsing.
> 
> COFF support is underway, it's just not included in this RFC.
> Amount of code is similar to elf.py.
> 
> Build is only tested on Linux x64_64.
> 
> If the community deems this RFC worth finishing, there are a few opens:
> 
> 1. Support for >65K section headers seems present in current pmdinfogen.
>     However, the data it reads is not used after. Is it really needed?
> 
Its used.
The support you're referring to is primarily the ability to extract the true
number of section headers from the ELF file (in the event that its more than
64k).  Without that, on very large binaries, you may not be able to find the
symbol table in the ELF file.

> 2. How much error-handling is required? This is a build-time tool,
>     and Python gives nice stacktraces. However, segfaults are possible
>     in Python version due to pointer handling. IMO, error checking
>     must be just sufficient to prevent silent segfaults.
> 
I'm not really sure what the question is here.  You need to handle errors in the
parsing process, we can't just have the tool crashing during the build.  How
thats handled is an implementation detail I would think.

> 3. On Unix, pmdinfogen is called for each object file extracted with ar
>     from an .a library by a shell script. On Windows, other tools
>     have to be used, shell script will not work. On the other hand, COFF
>     library format is quite simple. Would it be appropriate for
>     pmdinfogen to handle it to avoid intermediate script?
> 
I suppose you could, but extracting objects from archives seems outside the
scope of what pmdinfogen normally does.  What is the problem with using a shell
script on windows?  I thought WSL had support for executing bash syntax shell
scripts there?  Why not key off an environment variable to make the relevant
scripts do the right thing on your environment?

> ---
> Dmitry Kozlyuk (2):
>   pmdinfogen: prototype in Python
>   build: use Python pmdinfogen
> 
>  buildtools/elf.py        | 194 +++++++++++++++++++++++++++++++++++++++
>  buildtools/meson.build   |   3 +-
>  buildtools/pmdinfogen.py | 144 +++++++++++++++++++++++++++++
>  drivers/meson.build      |   2 +-
>  4 files changed, 340 insertions(+), 3 deletions(-)
>  create mode 100644 buildtools/elf.py
>  create mode 100755 buildtools/pmdinfogen.py
> 
> -- 
> 2.25.4
> 
> 

  parent reply	other threads:[~2020-06-22 12:41 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-22  0:45 Dmitry Kozlyuk
2020-06-22  0:45 ` [dpdk-dev] [RFC PATCH 1/2] pmdinfogen: prototype " Dmitry Kozlyuk
2020-06-22  0:45 ` [dpdk-dev] [RFC PATCH 2/2] build: use Python pmdinfogen Dmitry Kozlyuk
2020-06-22 12:41 ` Neil Horman [this message]
2020-06-22 19:39   ` [dpdk-dev] [RFC PATCH 0/2] pmdinfogen: rewrite in Python Dmitry Kozlyuk
2020-06-23 11:28     ` Neil Horman
2020-06-23 11:59       ` Bruce Richardson
2020-07-02  0:07       ` Dmitry Kozlyuk
2020-07-02  0:02 ` [dpdk-dev] [RFC PATCH v2 " Dmitry Kozlyuk
2020-07-02  0:02   ` [dpdk-dev] [RFC PATCH v2 1/3] pmdinfogen: prototype " Dmitry Kozlyuk
2020-07-02  0:02   ` [dpdk-dev] [RFC PATCH v2 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2020-07-02  0:02   ` [dpdk-dev] [RFC PATCH v2 3/3] doc/linux_gsg: require pyelftools for pmdinfogen Dmitry Kozlyuk
2020-07-06 12:52     ` Neil Horman
2020-07-06 13:24       ` Dmitry Kozlyuk
2020-07-06 16:46         ` Neil Horman
2020-07-08  0:53   ` [dpdk-dev] [PATCH v3 0/4] pmdinfogen: rewrite in Python Dmitry Kozlyuk
2020-07-08  0:53     ` [dpdk-dev] [PATCH v3 1/4] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-07-08  0:53     ` [dpdk-dev] [PATCH v3 2/4] build: use Python pmdinfogen Dmitry Kozlyuk
2020-07-08  0:53     ` [dpdk-dev] [PATCH v3 3/4] doc/linux_gsg: require pyelftools for pmdinfogen Dmitry Kozlyuk
2020-07-08  0:53     ` [dpdk-dev] [PATCH v3 4/4] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-07-08 21:23     ` [dpdk-dev] [PATCH v4 0/4] pmdinfogen: rewrite in Python Dmitry Kozlyuk
2020-07-08 21:23       ` [dpdk-dev] [PATCH v4 1/4] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-07-08 21:23       ` [dpdk-dev] [PATCH v4 2/4] build: use Python pmdinfogen Dmitry Kozlyuk
2020-07-21 14:04         ` Bruce Richardson
2020-07-21 14:59           ` Dmitry Kozlyuk
2020-07-08 21:23       ` [dpdk-dev] [PATCH v4 3/4] doc/linux_gsg: require pyelftools for pmdinfogen Dmitry Kozlyuk
2020-07-21 13:39         ` Bruce Richardson
2020-07-21 14:05           ` Bruce Richardson
2020-07-21 14:04         ` Bruce Richardson
2020-07-08 21:23       ` [dpdk-dev] [PATCH v4 4/4] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-07-09 10:42       ` [dpdk-dev] [PATCH v4 0/4] pmdinfogen: rewrite in Python Neil Horman
2020-07-21 13:51       ` Bruce Richardson
2020-09-27 21:47       ` [dpdk-dev] [PATCH v5 0/3] " Dmitry Kozlyuk
2020-09-27 21:47         ` [dpdk-dev] [PATCH v5 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-09-27 22:05           ` Stephen Hemminger
2020-09-27 21:47         ` [dpdk-dev] [PATCH v5 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2020-09-27 21:47         ` [dpdk-dev] [PATCH v5 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-09-27 23:15           ` Thomas Monjalon
2020-09-28  9:35         ` [dpdk-dev] [PATCH v5 0/3] pmdinfogen: rewrite in Python David Marchand
2020-10-04  1:59         ` [dpdk-dev] [PATCH v6 " Dmitry Kozlyuk
2020-10-04  1:59           ` [dpdk-dev] [PATCH v6 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-10-04  1:59           ` [dpdk-dev] [PATCH v6 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2020-10-04  1:59           ` [dpdk-dev] [PATCH v6 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-10-14 14:37           ` [dpdk-dev] [PATCH v6 0/3] pmdinfogen: rewrite in Python Maxime Coquelin
2020-10-14 15:40             ` Dmitry Kozlyuk
2020-10-14 18:31           ` [dpdk-dev] [PATCH v7 " Dmitry Kozlyuk
2020-10-14 18:31             ` [dpdk-dev] [PATCH v7 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-10-14 18:31             ` [dpdk-dev] [PATCH v7 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2020-10-14 18:31             ` [dpdk-dev] [PATCH v7 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-10-20 16:02             ` [dpdk-dev] [PATCH v7 0/3] pmdinfogen: rewrite in Python David Marchand
2020-10-20 17:45               ` Dmitry Kozlyuk
2020-10-20 22:09               ` Dmitry Kozlyuk
2020-10-20 17:44             ` [dpdk-dev] [PATCH v8 " Dmitry Kozlyuk
2020-10-20 17:44               ` [dpdk-dev] [PATCH v8 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2020-10-20 17:44               ` [dpdk-dev] [PATCH v8 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2020-10-21  9:00                 ` Bruce Richardson
2021-01-20  0:05                 ` Thomas Monjalon
2021-01-20  7:23                   ` Dmitry Kozlyuk
2021-01-20 10:24                     ` Thomas Monjalon
2021-01-22 20:31                       ` Dmitry Kozlyuk
2021-01-22 20:57                         ` Thomas Monjalon
2021-01-22 22:24                           ` Dmitry Kozlyuk
2021-01-23 11:38                             ` Thomas Monjalon
2021-01-24 20:52                               ` Dmitry Kozlyuk
2021-01-25  9:25                               ` Kinsella, Ray
2021-01-25 10:01                                 ` Kinsella, Ray
2021-01-25 10:29                                   ` David Marchand
2021-01-25 10:46                                     ` Kinsella, Ray
2021-01-25 11:03                                       ` Thomas Monjalon
2021-01-25 10:05                                 ` Dmitry Kozlyuk
2021-01-25 10:11                                   ` Kinsella, Ray
2021-01-25 10:31                                     ` Dmitry Kozlyuk
2020-10-20 17:44               ` [dpdk-dev] [PATCH v8 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2020-10-26 16:46                 ` Jie Zhou
2021-01-22 22:43               ` [dpdk-dev] [PATCH v9 0/3] pmdinfogen: rewrite in Python Dmitry Kozlyuk
2021-01-22 22:43                 ` [dpdk-dev] [PATCH v9 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2021-01-22 22:43                 ` [dpdk-dev] [PATCH v9 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2021-01-22 22:43                 ` [dpdk-dev] [PATCH v9 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2021-01-24 20:51                 ` [dpdk-dev] [PATCH v10 0/3] pmdinfogen: rewrite in Python Dmitry Kozlyuk
2021-01-24 20:51                   ` [dpdk-dev] [PATCH v10 1/3] pmdinfogen: add Python implementation Dmitry Kozlyuk
2021-01-24 20:51                   ` [dpdk-dev] [PATCH v10 2/3] build: use Python pmdinfogen Dmitry Kozlyuk
2021-01-25 10:12                     ` Thomas Monjalon
2021-01-24 20:51                   ` [dpdk-dev] [PATCH v10 3/3] pmdinfogen: remove C implementation Dmitry Kozlyuk
2021-01-25 13:13                   ` [dpdk-dev] [PATCH v10 0/3] pmdinfogen: rewrite in Python Thomas Monjalon
2021-01-25 16:08                     ` Brandon Lo
2021-02-02  8:48                       ` Tal Shnaiderman
2021-01-25 18:51                   ` Ali Alnubani
2021-01-25 22:15                     ` Dmitry Kozlyuk

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