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
