Re: [PATCH setup] Add new option '--compact-os'

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On May 12 16:14, Jon Turney wrote:
> On 08/05/2021 21:03, Christian Franke wrote:
> [...]
> > +bool io_stream_cygfile::compact_os_is_available = (OSMajorVersion () >= 10);
> 
> The documentation seems a bit vague, but are we really expecting this to
> work on Windows 10 1507?

I think this could even work under 8.1 from what I can see on MSDN.

> > +{
> > +  const char * const p = name.c_str();
> > +  if (!(!strncmp (p, "/bin/", 5) || !strncmp (p, "/sbin/", 6) || !strncmp (p, "/usr/", 5)))
> > +    return true; /* File is not in R/O tree. */
> > +  const size_t len = name.size(); /* >= 5 */
> > +  if (!strcmp (p + (len - 4), ".dll") || !strcmp (p + (len - 3), ".so"))
> > +    return true; /* Rebase will open file for writing which uncompresses the file. */
> > +  if (!strcmp (p + (len - 3), ".gz") || !strcmp (p + (len - 3), ".xz"))
> > +    return true; /* File is already compressed. */
> 
> Is this an assertion that there are no .bz2, .lzma, .zst etc. files in the
> install?

Another question is this: FILE_PROVIDER_COMPRESSION_LZX
"This algorithm is designed to be highly compact, and provides for small
 footprint for infrequently accessed data."

When running a shell script, certain executables (especially coreutils,
gawk, sed, grep, find) are not so very infrequently accessed.  Is this
compression really feasible for these binaries?  Did you compare shell
script performance with non-compressed, XPRESS16K and LZX compressed
/bin dir?

You know how Cygwin is already slow...


Thanks,
Corinna