On Sat, 4 Jul 2009, Phil Harman wrote:
If you reboot, your cpio(1) tests will probably go fast again, until someone uses mmap(2) on the files again. I think tar(1) uses read(2), but from my iPod I can't be sure. It would be interesting to see how tar(1) performs if you run that test before cp(1) on a freshly rebooted system.
Ok, I just rebooted the system. Now 'zpool iostat Sun_2540 60' shows that the cpio read rate has increased from (the most recently observed) 33 MB/second to as much as 132 MB/second. To some this may not seem significant but to me it looks a whole lot different. ;-)
I have done some work with the ZFS team towards a fix, but it is only currently in OpenSolaris.
Hopefully the fix is very very good. It is difficult to displace the many years of SunOS training that using mmap is the path to best performance. Mmap provides many tools to improve application performance which are just not available via traditional I/O.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
