Re: NFSv4/pNFS possible POSIX I/O API standards

[Ulrich Drepper <drepper@redhat.com>]

Ragnar Kjørstad wrote:
> I think Andreas already wrote that "ls --color" is the default in most
> distributions and needs to stat every file.

Remove the :ex entry from LS_COLORS and try again.


> "find" is already smart enough to not call stat when it's not needed,
> and make use of d_type when it's available. But in many cases stat is
> still needed (such as with -user)
> 
> find kernel_old -not -user 1002:
> 83.63% 173.11s  0.319ms  543338 lstat
> 16.31%  33.77s  5.242ms    6442 getdents64
>  0.03%   0.06s 62.882ms       1 execve
>  0.01%   0.03s  6.904ms       4 poll
>  0.01%   0.02s  8.383ms       2 connect

And how often do the scripts which are in everyday use require such a 
command?  And the same for the other programs.

I do not doubt that such a new syscall can potentially be useful.  The 
question is whether it is worth it given _real_ situations on today's 
systems.  And more so: on systems where combining the operations really 
makes a difference.

Exposing new data structures is no small feat.  It's always risky since 
something might require a change and then backward compatibility is an 
issue.

Introducing new syscalls just because a combination of two existing ones 
happens to be used in some programs is not scalable and not the 
Unix-way.  Small building blocks.  Otherwise I'd have more proposals 
which can be much more widely usable (e.g., syscall to read a file into 
a freshly mmaped area).  Nobody wants to go that route since it would 
lead to creeping featurism.  So it is up to the proponents of 
readdirplus to show this is not such a situation.

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
-
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html