On Mon, 12 Nov 2001, Lionel Bouton wrote:
>
> 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.
Wow. What a sleazy optimization - it can't be anything but a special case.
How do they do it anyway? By matching on the name Or by knowing what the
minor/major numbers of /dev/null are supposed to be on that particular
operating system?
And what's the _point_ of the optimization? I've never heard of a "tar
benchmark"..
Linus
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This archive was generated by hypermail 2b29 : Thu Nov 15 2001 - 21:00:31 EST