Re: File System Performance

[Gérard Roudier]

On Mon, 12 Nov 2001, Lionel Bouton wrote:

> Linus Torvalds wrote:
>
> >In article <[e-mail]>,
> >Andrew Morton  <[e-mail]> wrote:
> >
> >>It's tar.  It cheats.  It somehow detects that the
> >>output is /dev/null, and so it doesn't read the input files.
> >>
> >
> >Probably the kernel.
> >
> Seems not the case with gnu tar : write isn't even called once on the fd
> returned by open("/dev/null",...). In fact a "grep write" on the strace
> output is empty in the "tar cf /dev/null" case. Every file in the tar-ed
> tree is stat-ed but no-one is read-ed.

This kind of guessing from gnu tar seems utterly stupid to me. Developpers
that spend time for such kind of fake optimization either have time to
waste or brain to be fixed. Just my opinion.

  Gérard.