Re: [lm-sensors] [Patch] libsensors: Ignore directories and

[Andre Prendel <andre_prendel@gmx.de>]

On Thu, Feb 05, 2009 at 02:31:40PM +0100, Jean Delvare wrote:
> Hi Andre,
> 
> On Thu, 5 Feb 2009 11:45:36 +0100, Andre Prendel wrote:
> > On Thu, Feb 05, 2009 at 10:53:34AM +0100, Jean Delvare wrote:
> > > On Thu, 5 Feb 2009 10:03:31 +0100, Andre Prendel wrote:
> > > > I assume there are no hidden files in the directory, right? That's the
> > > > reason why I have removed this from condition.
> > > 
> > > I've never seen hidden files in sysfs except for sections
> > > in /sys/module. But the purpose of the original code was merely to skip
> > > "." and ".." anyway, not hidden files.
> > 
> > At another place (sysfs_foreach_classdev()) there is a comment
> > explaining the condition.
> > 
> > [...]
> >       if (ent->d_name[0] = '.')      /* skip hidden entries */
> >                         continue;
> > [...]
> 
> Indeed, but as I recall, the hidden entries we were worried about
> back then were just "." and "..". I don't expect it to make any
> difference anyway, as I doubt we'll ever have other hidden files or
> directories in class directories, nor do I expect non-directory (or
> link to directory) entries there.
> 
> > > (...)
> > > If you really care about performance (and I guess that's the sole
> > > purpose of your patch) then it's faster to check for ent->d_type !> > > DT_REG.
> > 
> > Indeed. That's even better.
> > 
> > > You can also move "name = ent->d_name" after this test to make
> > > the fast path even faster.
> > 
> > This should just avoid needless work and maybe potential errors in
> > parsing unexpected directory names.
> 
> I get the idea, and second it.
> 
> > > Out of curiosity, did you actually measure any performance improvement
> > > with your patch?
> > 
> > I didn't do a measurement. That wasn't the goal.
> 
> You might want to ask valgrind about it (I certainly will, being
> curious.)

So I will take a closer look at valgrind. I have used only the
memcheck tool so far. After that you will get an updated patch.
> 
> > P.S. To become familiar with the whole code and getting a better
> > understanding how things work, I walk through the code. And if I found
> > something that I would do in a different way, I send a patch to you :)
> 
> Sounds like a good plan, don't stop :)

I won't stop. :)

> Care to send an updated patch? I'll be happy to apply it.

Thanks
Andre

> -- 
> Jean Delvare

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