On Sunday 22 January 2012 20:52:43 Patrick O'Callaghan wrote: > On Sat, 2012-01-21 at 14:05 -0430, Patrick O'Callaghan wrote: > > This was really bothering me (I make frequent use of pendrives) so took > > another look at the above article, then > > at /usr/share/doc/kernel-doc-3.1.9/Documentation/vm/transhuge.txt, where > > it explains how to turn off the Transparent Huge Pages feature. I added > > transparent_hugepage=never to my boot params, rebooted, and the problem > > appears to have been fixed. > > I spoke too soon. The performance improvement must have been due to me > having just rebooted. In fact neither the boot param nor attempting to > write to /sys/kernel/mm/transparent_hugepage/enabled have any effect. > The latter *always* shows THP to be enabled and won't allow it to be > overwritten, even as root. After reading your previous post, I looked up the transhuge.txt doc and read it thoroughly. Echoing into the /sys/kernel/.../enabled did not work for me, but adding an option to the kernel command line did work. I have chosen to set up the "madvise" state rather than the "never" state, so I added "transparent_hugepage=madvise" to the GRUB_CMDLINE_LINUX line in /etc/default/grub, ran "grub2-mkconfig /boot/grub2/grub.cfg" to activate the change, and rebooted. After the reboot, the /sys/kernel/.../enabled file reads: always [madvise] never instead of the previous [always] madvise never I guess that means it works. :-) Before that I tried to put the echo command into /etc/rc.d/rc.local, but that didn't work. Initially I thought that there is a race condition in systemd between executing the rc.local and mounting /sys for rw, but I didn't properly investigate what actually went wrong --- it was easier to add a boot parameter. Also, boot parameter is guaranteed to work from the very start, while the echo version would influence only apps that have been started after the echo itself, which is kind of klunky for my taste. I haven't tried to write to USB since yesterday (I am just about to try now), but so far so good, and the kernel apparently acknowledges the "madvise" boot option. Now I'll see how USB is going to work --- a 2.2 GB file is about to be written... ;-) HTH, :-) Marko -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
