I wrote a SQL query that I thought I could share. This SQL query will show collected performance data for a specific machine for the last 30 minutes. I was working with a issue where some agents stopped sending performance data. Before we found the root cause and a fix, we configured this script in a monitor to give us an alert if the agent was not sending performance data. Info how to configure a monitor to run a SQL query can be found here.

select Path, ObjectName, CounterName, InstanceName, SampleValue, TimeSampled 
from PerformanceDataAllView pdv with (NOLOCK)
inner join PerformanceCounterView pcv on pdv.performancesourceinternalid = pcv.performancesourceinternalid
inner join BaseManagedEntity bme on pcv.ManagedEntityId = bme.BaseManagedEntityId
where path = 'dc01.contoso.local' AND (TimeSampled < GETUTCDATE() AND TimeSampled > DATEADD(MINUTE,-30, GETUTCDATE()))
order by timesampled DESC