These values are from org.apache.solr.handler.RequestHandlerBase, which is using org.apache.solr.util.stats.Timer for measuring. Timer has this constructor:
public Timer(TimeUnit durationUnit, TimeUnit rateUnit, Clock clock)
and this default constructor
public Timer() {
this(TimeUnit.MILLISECONDS, TimeUnit.SECONDS, Clock.defaultClock());
}
As you can see the default constructor instantiates the object with MILLISECONDS as durationUnit and SECONDS as rateUnit.
You can confirm this by setting a breakpoint in Timer.Timer(TimeUnit durationUnit, TimeUnit rateUnit, Clock clock).
So totalTime, avgTimePerRequest, medianRequestTime, 75thPcRequestTime, 95thPcRequestTime, 99thPcRequestTime, 999thPcRequestTime are all in ms.