tree ee057d71ca56dc39869fd1de75a44f23c47390cb
parent 37f7679fc956729a5e06509593c7cfc0d5801a2c
author Matthias Sohn <matthias.sohn@sap.com> 1562574016 +0200
committer Matthias Sohn <matthias.sohn@sap.com> 1563540355 +0200

Measure stored timestamp resolution instead of time to touch file

Measure granularity of timestamps stored in the filesystem by setting
and then getting lastModified timestamp until the read value changed.
Increase increment exponentially to limit number of iterations starting
with 1 microsecond since Java's FileTime (up to Java 12) truncates
timestamps to 1 microsecond resolution. The chosen algorithm yields 2000
steps between 1 ms and 2.5 s.

Also measure clock resolution and add that for the total timestamp
resolution. This avoids systematic measurement errors introduced by
doing IO to touch a file.

Change-Id: I9b37138619422452373e298d9d8c7cb2c384db3f
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>