On Wed, Jun 09, 2021 at 02:03:57AM +0300, Dmitry Kozlyuk wrote:
> 2021-06-04 16:44 (UTC-0700), Narcisa Ana Maria Vasile:
> [...]
> > diff --git a/lib/eal/windows/rte_thread.c b/lib/eal/windows/rte_thread.c
> > index 6ea1dc2a05..9e74a538c2 100644
> > --- a/lib/eal/windows/rte_thread.c
> > +++ b/lib/eal/windows/rte_thread.c
> > @@ -7,7 +7,8 @@
> > #include <rte_errno.h>
> > #include <rte_debug.h>
> > #include <rte_thread.h>
> > -#include <rte_windows.h>
> > +
> > +#include "eal_windows.h"
> >
> > struct eal_tls_key {
> > DWORD thread_index;
> > @@ -77,6 +78,130 @@ rte_thread_equal(rte_thread_t t1, rte_thread_t t2)
> > return t1.opaque_id == t2.opaque_id;
> > }
> >
> > +static int
> > +rte_convert_cpuset_to_affinity(const rte_cpuset_t *cpuset,
> > + PGROUP_AFFINITY affinity)
> > +{
> > + int ret = 0;
> > + PGROUP_AFFINITY cpu_affinity = NULL;
> > +
> > + memset(affinity, 0, sizeof(GROUP_AFFINITY));
> > + affinity->Group = (USHORT)-1;
> > +
> > + /* Check that all cpus of the set belong to the same processor group and
> > + * accumulate thread affinity to be applied.
> > + */
> > + for (unsigned int cpu_idx = 0; cpu_idx < CPU_SETSIZE; cpu_idx++) {
> > + if (!CPU_ISSET(cpu_idx, cpuset))
> > + continue;
> > +
> > + cpu_affinity = eal_get_cpu_affinity(cpu_idx);
> > +
> > + if (affinity->Group == (USHORT)-1) {
> > + affinity->Group = cpu_affinity->Group;
> > + } else if (affinity->Group != cpu_affinity->Group) {
> > + ret = EINVAL;
> > + goto cleanup;
> > + }
> > +
> > + affinity->Mask |= cpu_affinity->Mask;
> > + }
> > +
> > + if (affinity->Mask == 0) {
> > + ret = EINVAL;
> > + goto cleanup;
> > + }
> > +
> > +cleanup:
> > + return ret;
> > +}
>
> For v5 I asked a question that possibly got lost among other comments.
> Repeating the question for convenience:
>
> Just to be clear: is it a kernel limitation that a thread can only
> run on cores of one processor group, or do we impose it so that API
> is atomic (transactional), i.e. because one of multiple
> SetThreadGroupAffinity() calls may fail and leave thread partially
> affinitized?
The second reason (to ensure full affinitization). I am not aware of a kernel
limitation,
but I'll double check with Dmitry as we co-engineered this patch.
