[PATCH] optimize writer path in time_interpolator_get_counter()

Browse source

Christoph Lameter <clameter@engr.sgi.com>

When using a time interpolator that is susceptible to jitter there's
potentially contention over a cmpxchg used to prevent time from going
backwards.  This is unnecessary when the caller holds the xtime write
seqlock as all readers will be blocked from returning until the write is
complete.  We can therefore allow writers to insert a new value and exit
rather than fight with CPUs who only hold a reader lock.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

...

This commit is contained in:

Alex Williamson 2005-09-06 15:17:04 -07:00 • committed by Linus Torvalds

parent 9f4a6dce10

commit 486d46aefe

1 changed files with 13 additions and 4 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

17

kernel/timer.c

View file