Experimental Physics and
Industrial Control System

"Johnson, Andrew N. via Core-talk" <core-talk at aps.anl.gov> · Tue, 4 Aug 2020 01:07:58 +0000

No. I get non-zero milli- and microseconds in my time stamps now, but (counting after the decimal point) digits 7 through 9 of a %.9f seconds value are always zero.

- Andrew

-- 
Complicity is easy, Simplexity takes real work

> On Aug 3, 2020, at 6:54 PM, Michael Davidsaver <mdavidsaver at gmail.com> wrote:
> 
> On 8/3/20 4:02 PM, Johnson, Andrew N. via Core-talk wrote:
>>> On Aug 3, 2020, at 4:36 PM, APS Jenkins via Core-talk <core-talk at aps.anl.gov <mailto:core-talk at aps.anl.gov>> wrote:
>>> 
>>> See <https://jenkins.aps.anl.gov/job/epics-7.0/OS=mac/245/display/redirect?page=changes>
>> 
>> So the change I committed earlier to Darwin's osdTimeGetCurrent() speeds it up significantly, but apparently at the expense of not giving nanosecond precision any more – I guess that’s probably not terribly surprising.
> 
>> All my wall-clock timestamps now have 000 in the nanoseconds part,
> 
> Do I read this correctly?  Effective time resolution would be limited to 1 second on Mac?
> 
> 
>> although the monotonic clock isn’t affected as it uses a different kernel API.
>> 
>> The failures in the above Jenkins Mac build were these:
>> 
>>> simmTest.tap .............. 
>>> not ok 136 - time stamp is recent
>>> not ok 311 - time stamp is recent
>>> not ok 435 - time stamp is recent
>>> not ok 803 - time stamp is recent
>>> not ok 996 - time stamp is recent
>>> not ok 1171 - time stamp is recent
>>> Failed 6/1176 subtests 
>>>    (42 TODO tests unexpectedly succeeded)
>> 
>> The problem is that in several places the test code is doing this:
>> 
>>> testOk(epicsTimeLessThan(&now, mytime), "time stamp is recent");
>> 
>> which fails when now and *mytime are identical. I am changing that code to:
>> 
>>> double diff = epicsTimeDiffInSeconds(mytime, &now);
>>> testOk(diff >= 0.0, "time stamp is recent (%.9f sec)", diff);
>> 
>> Equality is now always allowed, and we get to see how different the timestamps actually are.
>> 
>> One of these (but not all) is inside a testTodoBegin("imprecise"); region.
>> 
>> - Andrew
>> 
>> -- 
>> Complexity comes for free, simplicity you have to work for.
>> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System