|| ||"Jan Beulich" <JBeulich@novell.com> |
|| ||<email@example.com>, <firstname.lastname@example.org>, <email@example.com> |
|| ||[PATCH 0/3] x86: enlightenment for ticket spinlocks |
|| ||Fri, 29 Jan 2010 08:00:13 +0000|
|| ||"Jeremy Fitzhardinge" <firstname.lastname@example.org>, <email@example.com>|
|| ||Article, Thread
With the pv-ops based spinlocks reportedly having measurable overhead
on native execution, and with them also not easily fit (at least) fully
virtualized Xen guests, this patch series introduces a replacement
mechanism based on alternative instruction patching, and then uses it
for fully virtualized Xen guests. While coded to be orthogonal to
pv-ops, it really isn't, and it shouldn't be difficult to make pv-ops guests
use this in place of pv-ops spin locks.
The only additional overhead this introduces for native execution is
the writing of the owning CPU in the lock acquire paths. If this is
considered a problem, even that code could be eliminated for native
execution (by further alternative instruction patching).
(1) base implementation
(2) Xen implementation
(3) [optional] eliminate on NOPs in unlock path (introduced in (1))
Signed-off-by: Jan Beulich <firstname.lastname@example.org>
Cc: Jeremy Fitzhardinge <email@example.com>
[2. text/plain; linux-2.6.33-rc5-virt-spinlocks-xen.patch]...
[3. text/plain; linux-2.6.33-rc5-virt-spinlocks-base.patch]...
[4. text/plain; linux-2.6.33-rc5-virt-spinlocks-no-nop.patch]...