Re: [PATCH] x86: Reenable TSC sync check at boot, even withNONSTOP_TSC

[Suresh Siddha]

On Thu, 2009-12-17 at 13:27 -0700, Pallipadi, Venkatesh wrote:
> Commit 83ce4009 did the following change
> If the TSC is constant and non-stop, also set it reliable.
> 
> But, there seems to be few systems that will end up with TSC warp across
> sockets, depending on how the cpus come out of reset. Skipping TSC sync
> test on such systems may result in time inconsistency later.
> 
> So, reenable TSC sync test even on constant and non-stop TSC systems.
> Set, sched_clock_stable to 1 by default and reset it in
> mark_tsc_unstable, if TSC sync fails.
> 
> This change still gives perf benefit mentioned in 83ce4009 for systems
> where TSC is reliable.
> 
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>

Acked-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/