Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Skip to content
Commit 14be1f74 authored by Dimitri Sivanich's avatar Dimitri Sivanich Committed by Ingo Molnar
Browse files

x86: Fix sched_clock_cpu for systems with unsynchronized TSC



On UV systems, the TSC is not synchronized across blades.  The
sched_clock_cpu() function is returning values that can go
backwards  (I've seen as much as 8 seconds) when switching
between cpus.

As each cpu comes up, early_init_intel() will currently set the
sched_clock_stable flag true.  When mark_tsc_unstable() runs, it
clears the flag, but this only occurs once (the first time a cpu
comes up whose TSC is not synchronized with cpu 0).  After this,
early_init_intel() will set the flag again as the next cpu comes
up.

Only set sched_clock_stable if tsc has not been marked unstable.

Signed-off-by: default avatarDimitri Sivanich <sivanich@sgi.com>
Acked-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100301174815.GC8224@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 13dda80e
Loading
Loading
Loading
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment