Phillip Susi <psusi@xxxxxxxxxx> wrote: > > On Sat, Dec 15, 2012 at 12:54:48AM +0000, Eric Wong wrote: > >> "strace -T" timing on an uncached, one gigabyte file: > >> > >> Before: fadvise64(3, 0, 0, POSIX_FADV_WILLNEED) = 0 <2.484832> > >> After: fadvise64(3, 0, 0, POSIX_FADV_WILLNEED) = 0 <0.000061> > > It shouldn't take 2 seconds to queue up some async reads. Are you > using ext3? The blocks have to be mapped in order to queue the reads, > and without ext4 extents, this means the indirect blocks have to be > read and can cause fadvise to block. You're right, I originally tested on ext3. I just tested an unpatched 3.7.9 kernel with ext4 and is much faster (~250ms). I consider ~250ms acceptable for my needs. Will migrate the rest of my setup to ext4 soon, thanks for the tip! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>