On Sat, Jan 14, 2023, at 7:18 PM, Mike Frysinger wrote: > Rather than assume such coarse delays, re-use existing logic for > probing the current filesystem resolution. This speeds up the > testsuite significantly. On my system, it speeds -j1 up quite a > lot -- by ~30%. While I didn't gather many samples to produce a > statistically significant distribution, my runs seem to be fairly > consistent with the values below with deviations of <1 minute.
No objection to this patch in itself, but I want to make sure you're aware that the "existing logic for probing the current filesystem resolution" has a bug where, if you start running the script at just the wrong time, it will erroneously detect a finer timestamp resolution than the system actually supports. For instance, if we can sleep for 0.1 second, the filesystem's timestamp resolution is 2s, and the sleep loop happens to start executing at 0h00m59.9s, then it'll tick over to 0h01m00.0s and conftest.file.a and conftest.file.b will have distinct timestamps. This happens to me quite reliably: whenever I try to run the Automake test suite inside AFS, I'll get a couple of spurious test failures because of this bug. zw
