On Thu, Jun 30, 2022 at 03:21:15PM +0200, Jakub Jelinek via Gcc-patches wrote:
> On Thu, Jun 30, 2022 at 01:40:24PM +0200, Jakub Jelinek via Gcc-patches wrote:
> > > +/* The initial ICV values for the host, which are configured with
> > > environment
> > > + variables without a suffix, e.g. OMP_NUM_TEAMS. */
> > > +struct gomp_initial_icvs gomp_initial_icvs_none;
> > > +
> > > +/* Initial ICV values that were configured for the host and for all
> > > devices by
> > > + using environment variables like OMP_NUM_TEAMS_ALL. */
> > > +struct gomp_initial_icvs gomp_initial_icvs_all;
> > > +
> > > +/* Initial ICV values that were configured only for devices (not for the
> > > host)
> > > + by using environment variables like OMP_NUM_TEAMS_DEV. */
> > > +struct gomp_initial_icvs gomp_initial_icvs_dev;
> >
> > As I said last time, I don't like allocating these
> > all the time in the data section of libgomp when at least for a few upcoming
> > years, most users will never use those suffixes.
> > Can't *_DEV and *_ALL go into the gomp_initial_icv_dev_list
> > chain too, perhaps
>
> Sorry, forgot to finish sentence, I meant perhaps with dev_num of some magic
> negative constants, and ensure that the all entry goes e.g. first in the
> list, then dev and then the rest, so when filling up say what values to copy
> to some device, it would start with the defaults, then if all is present
> overwrite from selected all vars, then if non-host and dev is present,
> overwrite from selected dev vars and finally overwrite from selected
> specific device vars.
One more thing. If we go just with gomp_initia_icvs_none and the all/dev
are in the list together with the rest, it would be enough not to use
multi-bit flags, but just single bit, has this env var been specified here
or not. So, as long as there are <= 32 vars (excluding the ones that don't
have suffixed variants), we can use unsigned int bitmask indexed by the
enum, or if we need <= 64 vars we could use unsigned long long int bitmask.
And have one such bitmask next to gomp_initial_icvs_none and another one in
each list node.
Jakub
