On Fri, 2017-11-03 at 10:28 -0200, Gustavo Romero wrote: > Hi Cyril! > > On 01-11-2017 20:10, Cyril Bur wrote: > > Thanks Gustavo, > > > > I do have one more thought on an improvement for this test which is > > that: > > + /* Counter for busy wait * > > + uint64_t counter = 0x1ff000000; > > is a bit fragile, what we should do is have the test work out long it > > should spin until it reliably gets a TM_CAUSE_FAC_UNAV failure and then > > use that for these tests. > > > > This will only become a problem if we were to change kernel heuristics > > which is fine for now. I'll try to get that added soon but for now this > > test has proven too useful to delay adding as is. > > I see. Yup, 'counter' value was indeed determined experimentally under many > different scenarios (VM and BM, different CPU loads, etc). At least if the > heuristics changes hurting the test it will catch that pointing out that > the expected failure did not happen, like: > > Checking if FP/VEC registers are sane after a FP unavailable exception... > If MSR.FP=0 MSR.VEC=0: > Expecting the transaction to fail, but it didn't > FP ok VEC ok > ... > > So it won't let the hurting change pass fine silently :-) >
Yeah, all for merging as is. It would be nice so that when someone does make a heuristic change they don't also have to go fix tests - there is nothing more annoying than a fragile test suite. > > > > Signed-off-by: Gustavo Romero <grom...@linux.vnet.ibm.com> > > > Signed-off-by: Breno Leitao <lei...@debian.org> > > > Signed-off-by: Cyril Bur <cyril...@gmail.com> > > Thanks a lot for reviewing it. > > Cheers, > Gustavo >
