prefer tsc timecounter when it's good
cswiger at mac.com
Thu Apr 7 18:59:25 UTC 2011
On Apr 7, 2011, at 10:12 AM, Andriy Gapon wrote:
> what do you think about the following change?
> The idea is mark TSC as the best timecounter when it's invariant and synchronized
> between cores.
> Unfortunately I don't have code to auto-detect the synchronization and keep
> relying on the corresponding tunable. I thought about auto-setting it for
> single-package configurations, but even that information is currently not trivial
> to get out of our mp (i386/amd64) machdep code.
In theory, most machines with P-state invariant TSCs should have their counters completely synchronized, even if there are multiple packages:
...the exception would be very large machines with multiple mainboards.
More information about the freebsd-current