lkml.org 
[lkml]   [2017]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 1/9] x86/tsc: Provide tsc=unstable boot parameter
Since the clocksource watchdog will only detect broken TSC after the
fact, all TSC based clocks will likely have observed non-continuous
values before/when switching away from TSC.

Therefore only thing to fully avoid random clock movement when your
BIOS randomly mucks with TSC values from SMI handlers is reporting the
TSC as unstable at boot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/tsc.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -374,6 +374,8 @@ static int __init tsc_setup(char *str)
tsc_clocksource_reliable = 1;
if (!strncmp(str, "noirqtime", 9))
no_sched_irq_time = 1;
+ if (!strcmp(str, "unstable"))
+ mark_tsc_unstable("boot parameter");
return 1;
}


\
 
 \ /
  Last update: 2017-04-21 19:09    [W:0.072 / U:0.440 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site