Messages in this thread | | | Date | Sat, 23 Jun 2018 15:32:36 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v12 03/11] x86/tsc: redefine notsc to behave as tsc=unstable |
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On Thu, 21 Jun 2018, Pavel Tatashin wrote: > Currently, notsc kernel parameter disables the use of tsc register by > sched_clock(). However, this parameter does not prevent linux from > accessing tsc in other places in kernel. > > The only rational to boot with notsc is to avoid timing discrepancies on > multi-socket systems where different tsc frequencies may present, and thus > fallback to jiffies for clock source. > > However, there is another method to solve the above problem, it is to boot > with tsc=unstable parameter. This parameter allows sched_clock() to use tsc > but in case tsc is outside of expected interval it is corrected back to a > sane value. > > This is why there is no reason to keep notsc, and it can be removed. But, > for compatibility reasons we will keep this parameter but change its > definition to be the same as tsc=unstable. > > Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> > Reviewed-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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