I recently upgraded our NFS fileserver to an ext4 filesystem, and since
then we've been having clock skew warnings from make (3.81). Because
the ext3 filesystem that was previously running on the NFS server didn't
support high-precision timestamps, we didn't have clock skew warnings
because an hourly cron job kept the clocks in relatively close sync.
However, since ext4 does support sub-second timestamps, we're getting
warnings about clock skews on the order of a few milliseconds. I tried
adding our target objects to the .LOW_RESOLUTION_TIME target, however
now we're getting a warning about
make: *** Warning: .LOW_RESOLUTION_TIME file .lib_deps has a high
resolution time stamp
make: warning: Clock skew detected. Your build may be incomplete.
Since asking to have system clocks of NFS clients and servers synced to
sub-millisecond precision is a bit excessive, is there a way (or feature
request: could there be a way) to set the threshold for clock skews
either via a runtime Makefile directive, or an environment variable? I
can't see any other way to eliminate these warnings without reverting
back to ext3 (which isn't happening). If it's a hard-coded value, there
should be at least a little room for slop in there (~5 milliseconds?)
due to network lag, etc. Even on a point-to-point network, there's
going to be one-way transit times of a millisecond or two.
Cheers
