On Sun, 28 Nov 2010, Herbert Xu wrote: > On Sat, Sep 04, 2010 at 07:35:04PM +0000, Jilles Tjoelker wrote: > > > > > I attached an updated patch that corrects this pb by discarding the > > > buffer when opening a new file. > > > > This discarding is still bad as it throws away valid data if the open > > file description is shared. This happens if stdin is redirected inside a > > I'm with Jilles on this. I also don't particularly feel like > bloating dash just because of the borked /proc interface when > there is a perfectly adequate work-around in "cat". > > value=$(cat /proc/file)
I wouldn't call that "a perfectly adequate work-around", but a painful and unadequate work-around. And this example will hopefully show why: $ dash -c 'loops=10000; while [ $loops -gt 0 ];do read MAX </proc/sys/kernel/pid_max; loops=$(($loops - 1)); done; times' 0m0.180000s 0m0.100000s 0m0.000000s 0m0.000000s total: 0.28s $ dash -c 'loops=10000; while [ $loops -gt 0 ];do MAX=$(cat /proc/sys/kernel/pid_max); loops=$(($loops - 1)); done; times' 0m0.280000s 0m1.330000s 0m3.840000s 0m1.560000s total: 7.01s That is, the first example is 24x more efficient than the second. And that realy _matters_, I would say. Cheers, -- Cristian -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
