Re: Reduce timing overhead of EXPLAIN ANALYZE using rdtsc?

> I do think its reasonable for us to check this directly, since we're
> already working with cpuid information anyway, and we also need the
> TSC frequency data in the Hypervisor specific leafs (i.e. its not just
> about getting the VM vendor name itself). For example, I don't think
> HyperV provides TSC frequency in 0x40000010 - it was something VMware
> added initially, that KVM subsequently added.

And then we have a hard dependency on systemd, where at the moment the
user can try to use RDTSC also on systems without.

>> Also it would be cool if the patch would provide some way of reporting back
>> what clock_source was really used in case of FAST_CLOCK_SOURCE_AUTO.
>> Something like huge_pages_status or some elog(DEBUG).
> 
> Agreed, I think that would be useful.

+1

--
David Geier