Messages in this thread | | | Date | Sat, 6 Jul 2013 12:50:10 +0200 | From | Peter Zijlstra <> | Subject | Re: [URGENT rfc patch 0/3] tsc clocksource bug fix |
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On Fri, Jul 05, 2013 at 11:50:05PM +0200, Thomas Gleixner wrote: > On Fri, 5 Jul 2013, Peter Zijlstra wrote: > > On Fri, Jul 05, 2013 at 05:24:09PM +0200, Thomas Gleixner wrote: > > > See arch/x86/kernel/tsc.c > > > > > > We disable the watchdog for the TSC when tsc_clocksource_reliable is > > > set. > > > > > > tsc_clocksource_reliable is set when: > > > > > > - you add tsc=reliable to the kernel command line > > > > Ah, I didn't know about that one, useful. > > > > > - boot_cpu_has(X86_FEATURE_TSC_RELIABLE) > > > > > > X86_FEATURE_TSC_RELIABLE is a software flag, set by vmware and > > > moorsetown. So all other machines keep the watchdog enabled. > > > > Right.. I knew it was enabled on my machines even though they normally > > have usable TSC. > > Yeah, but our well justified paranoia still prevents us from trusting > these CPU flags. Maybe some day BIOS is going to be replaced by > something useful. You know: Hope springs eternal....
Oh quite agreed. Its just that at several times I've wanted to disable the thing. Now I know you can do using the kernel cmdline. Previously I had to wreck code -- not that much harder really :-)
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