Re: [PATCH 1/2] sched: Optimize build_sched_domains() for saving first SD node for a cpu

Hi, Viresh

On 06/04/2013 07:20 PM, Viresh Kumar wrote: [snip]

diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 58453b8..638f6cb 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6533,16 +6533,13 @@ static int build_sched_domains(const struct cpumask *cpu_map, sd = NULL; for (tl = sched_domain_topology; tl->init; tl++) { sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);

• 	if (!*per_cpu_ptr(d.sd, i))
  

What about: if (tl == sched_domain_topology)

It cost less than per_cpu_ptr(), isn't it?

Regards, Michael Wang

• 		*per_cpu_ptr(d.sd, i) = sd;
  if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
  	sd->flags |= SD_OVERLAP;
  if (cpumask_equal(cpu_map, sched_domain_span(sd)))
  	break;
  

  }

• while (sd->child)
  

• 	sd = sd->child;
  

• *per_cpu_ptr(d.sd, i) = sd;
  

  }

  /* Build the groups for the domains */