Re: [netcdfgroup] Intel 15 and netCDF 4.3.2: Issues with Optimization?

• To: Russ Rew <russ@xxxxxxxxxxxxxxxx>
• Subject: Re: [netcdfgroup] Intel 15 and netCDF 4.3.2: Issues with Optimization?
• From: "Thompson, Matt (GSFC-610.1)[SCIENCE SYSTEMS AND APPLICATIONS INC]" <matthew.thompson@xxxxxxxx>
• Date: Wed, 3 Sep 2014 07:30:49 -0400

On 09/02/2014 03:14 PM, Russ Rew wrote:

Hi Matt,

    .
    ​..​
    Since type_size is determined from things within var, who knows if a
    struct is clobbered or what.

    Has anyone else seen this? I suppose for now I can just point to the
    debug-netcdf build so I can continue developing/testing with Intel
    15 though I don't know what the cost of running netCDF at -O0 is.


​In version 4.3.2, type_size is computed just above the code you're showing:

​                       if (var->type_info->nc_type_class == NC_STRING)
                            type_size = sizeof(char *);
                         else
                            type_size = var->type_info->size;

​It's hard to believe that the code would get sizeof(char *) wrong, so
I'm betting ​var->type_info->size is somehow getting 0.  If you could
send a dump of *var and *var->type_info from the debugger just before
the FPE happens, I might be able to determine whether these structures
are getting clobbered.  Of course, that could still be a problem in the
library.

In answer to your other question, I doubt that -O0 makes netCDF access
noticably slower than -O2 ...

Good to know. Thanks.

Matt


--
Matt Thompson          SSAI, Sr Software Test Engr
NASA GSFC, Global Modeling and Assimilation Office
Code 610.1, 8800 Greenbelt Rd, Greenbelt, MD 20771
Phone: 301-614-6712              Fax: 301-614-6246

• References:
  • [netcdfgroup] Intel 15 and netCDF 4.3.2: Issues with Optimization?
    • From: Thompson, Matt (GSFC-610.1)[SCIENCE SYSTEMS AND APPLICATIONS INC]