On Wed, Mar 11, 2020 at 02:05:33PM +0000, Qais Yousef wrote: > On 03/10/20 18:01, Josh Don wrote: > > From: Paul Turner <pjt@xxxxxxxxxx> > > > > Currently, when updating the affinity of tasks via either cpusets.cpus, > > or, sched_setaffinity(); tasks not currently running within the newly > > specified mask will be arbitrarily assigned to the first CPU within the > > mask. > > > > This (particularly in the case that we are restricting masks) can > > result in many tasks being assigned to the first CPUs of their new > > masks. > > > > This: > > 1) Can induce scheduling delays while the load-balancer has a chance to > > spread them between their new CPUs. > > 2) Can antogonize a poor load-balancer behavior where it has a > > difficult time recognizing that a cross-socket imbalance has been > > forced by an affinity mask. > > > > This change adds a new cpumask interface to allow iterated calls to > > distribute within the intersection of the provided masks. > > > > The cases that this mainly affects are: > > - modifying cpuset.cpus > > - when tasks join a cpuset > > - when modifying a task's affinity via sched_setaffinity(2) > > > > Co-developed-by: Josh Don <joshdon@xxxxxxxxxx> > > Signed-off-by: Josh Don <joshdon@xxxxxxxxxx> > > Signed-off-by: Paul Turner <pjt@xxxxxxxxxx> > Anyway, for the API. > > Reviewed-by: Qais Yousef <qais.yousef@xxxxxxx> > Tested-by: Qais Yousef <qais.yousef@xxxxxxx> Thanks guys!
