Re: Default value to field SCAN

[Gabriel de Souza Fedel <gabriel.fedel@lnls.br>]

Hi Andrew,

Em 03-01-2017 17:55, Andrew Johnson escreveu:
> Hi Gabriel,
>
> On 01/03/2017 12:58 PM, Gabriel de Souza Fedel wrote:
> > > > I'm having problems with a set of records without SCAN field that are
> > > > consuming a lot of CPU, and receiving this messages:
> > > >
> > > > dbScan warning from '.2 second' scan thread:
> > > >         Scan processing averages 0,00 seconds (0,00 .. 0,02).
> > > >         Over-runs have now happened 283681 times in a row.
> > > >         To fix this, move some records to a slower scan rate.
> > > >
> > > > dbScan warning from '.5 second' scan thread:
> > > >         Scan processing averages 0,00 seconds (0,00 .. 0,03).
> > > >         Over-runs have now happened 290049 times in a row.
> > > >         To fix this, move some records to a slower scan rate.
> > > >
> > > > dbScan warning from '.1 second' scan thread:
> > > >         Scan processing averages 0,00 seconds (0,00 .. 0,03).
> > > >         Over-runs have now happened 278431 times in a row.
> > > >         To fix this, move some records to a slower scan rate.
> > > >
> > > > If i remove small choices from dbd file (.1, .2 and .5 seconds) solves
> > > > the problem. Apparently the records are being created with all SCAN
> > > > values...some idea to solve this?
> > > These symptoms are very strange; as Mark Rivers suggested those average
> > > processing times should be larger than the nominal scan period. Please
> > > cd to your base/src/libCom/test directory and type 'make runtests' and
> > > report any test failures here. Also please try running the IOC with the
> > > LANG environment variable set to "C" instead of whatever it is currently
> > > set to in case that is causing the problem.
> > First, setting LANG=C stop this messages....why?
> Interesting, what is your normal value for LANG?
On this machine, the LANG is "pt_BR.UTF-8". On pt_BT decimal separator 
is ",".
> The IOC works out what scan periods to create by converting the menuScan
> choice strings into a floating-point number using strtod(). It looks
> like in your case the strtod() routine is not recognizing the '.'
> character as the decimal separator (in the warning messages you showed
> the printf() output uses ',' as the decimal separator which is what
> suggested this to me) so for the sub-second periodic scan threads the
> scan period is being set to 0, hence the above warnings. By setting LANG
> to C you change the decimal separator that strtod() recognizes back to
> '.' and now the IOC can correctly convert those fractional-second
> periods into a non-zero value.
Hum! Interesting! Thank you for the explanation!

The stranger thing is this is the first time I have this problem.
> You could try editing the choice strings in your menuScan.dbd file to be
> ",1 second" ",2 second" and ",5 second" but that solution risks
> incompatibility with any .db files that use the original strings in
> their SCAN field values (especially for .db files that you may use from
> support modules such as synApps or Asyn).
>
> Can you find a slightly different locale setting for LANG (or maybe just
> for the LC_NUMERIC variable) that will allow both ',' and '.' to be used
> as decimal separators in your language? Since none of the European EPICS
> users have complained about this I suspect there may be one, but this
> isn't an area that I know very much about — have any other EPICS users
> already resolved this kind of problem?
For my machine, I can change LANG (or LC_NUERIC), that probably don't 
will cause any problem. But I will find why this happens only with this IOC.
> > Secondly, I ran the tests, and some errors happened (attached), but
> > doesn't look to be anything related to that messages.
> True, that failure probably just means that the test program wasn't able
> to write to the Base directories — you can ignore this.
Thank you again,

Gabriel

> - Andrew
--
Gabriel Fedel
Software de Operação das Linhas de Luz
Laboratório Nacional de Luz Síncrotron – (LNLS)
Centro Nacional de Pesquisa em Energia e Materiais (CNPEM)
gabriel.fedel@lnls.br | +55 (19) 3512 1226
www.lnls.cnpem.br