Re: [Help-gsl] GSL 1.16 gsl_interp_accel_find not threadsafe?

[Patrick Alken]

Hard to say without any example code, but are you trying to use the same 
accel object from all the threads? Each thread will need its own 
interpolator and accel workspace. From the two lines you posted, I don't 
see any global variables or anything that would cause problems as long 
as each thread has its own accel workspace.

Patrick

On 03/21/2016 12:34 PM, Leek, Jim wrote:
> I am using GSL in an openMP program.  It usually goes pretty well, but I 
> recently ran a problem where I started getting random results (the 
> deterministic problem returned wildly different results on each run.)
>
> I was finally able to get Intel Inspector to give me a clue.  It says there is 
> a data race in gsl_intep_accel_find at:
>
> Line 210,211:
>    a->miss_count++;
>    a->cache - gsl_interp_bsearch(ca, x, x_intex, len-1)
>
> The call stack is:
> gsl_spline_eval_integ:190
> gsl_intep_eval_integ:273
> cspline_eval_integ:403
> gsl_interp_accel_find:211
>
> Avoiding calling this in the threading region does seem to solve the issue.
>
> 1) Is this a known issue?
> 2) Is there a known way to get around it?
> 3) Is it already fixed in a newer version of GSL?
>
> Thanks,
> Jim