Re: [PATCH 0/11] renaming argv_array

From: Jeff King <peff@peff.net>
Date: Aug 12, 2020, 17:08 UTC
Message-ID: <20200812170849.GA43566@coredump.intra.peff.net>
In-Reply-To: <045ea49b-7165-0f45-e670-a24bf648f880@web.de>

On Wed, Aug 12, 2020 at 06:23:01PM +0200, René Scharfe wrote:

Show 12 quoted lines

> > This seems to be related to setting SPATCH_BATCH_SIZE to "0". It used to make
> > things go much faster (if you had enough memory), but now seems to just
> > consume tons of CPU. Setting it to "1" finishes the whole thing in ~13
> > minutes of CPU (~2m wall-clock).
> 
> This bit me as well, and I settled with SPATCH_BATCH_SIZE = 10.  With
> MAKEFLAGS += -j3 I get these number, which are quite similar to yours
> (except I don't dare use more cores due to cooling issues..):
> 
>   real	4m12,393s
>   user	12m15,447s
>   sys	0m10,418s

Interestingly, that was slower for me (2m47s wall-clock, with 27m of CPU). Using "2" is slightly faster than "1". But "3" is a little less fast, and "4" is slower than "1". So...no clue what is going on.

Show 5 quoted lines

> > So that's at least a path forward, but in general I have been frustrated
> > with operational aspects of coccinelle like this.
> 
> And I was a bit shocked when Coccinelle's testing package became
> unmaintained for a while and I had to compile it from source.

Yeah, I've had various issues with the packaging. For a long time they had 1.0.7 in experimental, but with no python support. I wonder if it's worth starting to use python scriptlets in our coccinelle rules, as described in 4d168e742a (coccinelle: use <...> for function exclusion, 2018-08-28). They're faster and IMHO easier to understand.

Of course I tried it out and got some inscrutable errors:

  SPATCH contrib/coccinelle/object_id.cocci
  init_defs_builtins: /usr/bin/../lib/coccinelle/standard.h
  Python path configuration:
    PYTHONHOME = '/lib/x86_64-linux-gnu/..'
    PYTHONPATH = '/usr/bin/../lib/coccinelle/python'
    program name = 'python3'
    isolated = 0
    environment = 1
    user site = 1
    import site = 1
    sys._base_executable = '/usr/bin/python3'
    sys.base_prefix = '/lib/x86_64-linux-gnu/..'
    sys.base_exec_prefix = '/lib/x86_64-linux-gnu/..'
    sys.executable = '/usr/bin/python3'
    sys.prefix = '/lib/x86_64-linux-gnu/..'
    sys.exec_prefix = '/lib/x86_64-linux-gnu/..'
    sys.path = [
      '/usr/bin/../lib/coccinelle/python',
      '/lib/x86_64-linux-gnu/../lib/python38.zip',
      '/lib/x86_64-linux-gnu/../lib/python3.8',
      '/lib/x86_64-linux-gnu/../lib/python3.8/lib-dynload',
    ]
  Fatal Python error: init_fs_encoding: failed to get the Python codec of the filesystem encoding
  Python runtime state: core initialized
  ModuleNotFoundError: No module named 'encodings'

Fun.

-Peff