Thanks for the further measurements. It sounds like in the current version of GNU/Linux, POSIX_FADV_NOREUSE | POSIX_FADV_SEQUENTIAL is still much slower than O_DIRECT, even with kernel tweaking, so that is an argument for having a new option for 'cp', 'mv', and 'install'. It would be helpful to know, though, why the performance difference is so great -- can you ask the kernel folks about that?
If we head this direction, one idea is to mimic the iflag and oflag options that are already in 'dd'. Thus: cp --iflag=direct --oflag=direct SOURCE DEST would have the effect that you want. One could also specify other combinations, e.g., --iflag='direct,noctty'. Perhaps it would also make sense to have a combined --ioflag=direct option, for convenience. _______________________________________________ Bug-coreutils mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-coreutils
