s390/vtime: limit MT scaling value updates
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 3 Aug 2015 14:16:40 +0000 (16:16 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Tue, 4 Aug 2015 12:26:17 +0000 (14:26 +0200)
commitf341b8dff9823a969be5fb3c958e5cb305ac67e8
tree95320cc56a2f9af389ffa3bf17e64e1f8dc289d6
parent5a7ff75a0c63222d138d944240146dc49a9624e1
s390/vtime: limit MT scaling value updates

The MT scaling values are updated on each calll to do_account_vtime.
This function is called for each HZ interrupt and for each context
switch. Context switch can happen often, the STCCTM instruction
on this path is noticeable. Limit the updates to once per jiffy.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/vtime.c