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authorSiddha, Suresh B <suresh.b.siddha@intel.com>2006-03-27 01:15:22 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-27 08:44:43 -0800
commit1e9f28fa1eb9773bf65bae08288c6a0a38eef4a7 (patch)
treeccfa4927ebc7a8f663f9ac9e7789a713a33253ff /kernel/sched.c
parent77e4bfbcf071f795b54862455dce8902b3fc29c2 (diff)
[PATCH] sched: new sched domain for representing multi-core
Add a new sched domain for representing multi-core with shared caches between cores. Consider a dual package system, each package containing two cores and with last level cache shared between cores with in a package. If there are two runnable processes, with this appended patch those two processes will be scheduled on different packages. On such systems, with this patch we have observed 8% perf improvement with specJBB(2 warehouse) benchmark and 35% improvement with CFP2000 rate(with 2 users). This new domain will come into play only on multi-core systems with shared caches. On other systems, this sched domain will be removed by domain degeneration code. This new domain can be also used for implementing power savings policy (see OLS 2005 CMP kernel scheduler paper for more details.. I will post another patch for power savings policy soon) Most of the arch/* file changes are for cpu_coregroup_map() implementation. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c73
1 files changed, 68 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index a96a05d23262..8a8b71b5751b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5574,11 +5574,31 @@ static int cpu_to_cpu_group(int cpu)
}
#endif
+#ifdef CONFIG_SCHED_MC
+static DEFINE_PER_CPU(struct sched_domain, core_domains);
+static struct sched_group sched_group_core[NR_CPUS];
+#endif
+
+#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
+static int cpu_to_core_group(int cpu)
+{
+ return first_cpu(cpu_sibling_map[cpu]);
+}
+#elif defined(CONFIG_SCHED_MC)
+static int cpu_to_core_group(int cpu)
+{
+ return cpu;
+}
+#endif
+
static DEFINE_PER_CPU(struct sched_domain, phys_domains);
static struct sched_group sched_group_phys[NR_CPUS];
static int cpu_to_phys_group(int cpu)
{
-#ifdef CONFIG_SCHED_SMT
+#if defined(CONFIG_SCHED_MC)
+ cpumask_t mask = cpu_coregroup_map(cpu);
+ return first_cpu(mask);
+#elif defined(CONFIG_SCHED_SMT)
return first_cpu(cpu_sibling_map[cpu]);
#else
return cpu;
@@ -5676,6 +5696,17 @@ void build_sched_domains(const cpumask_t *cpu_map)
sd->parent = p;
sd->groups = &sched_group_phys[group];
+#ifdef CONFIG_SCHED_MC
+ p = sd;
+ sd = &per_cpu(core_domains, i);
+ group = cpu_to_core_group(i);
+ *sd = SD_MC_INIT;
+ sd->span = cpu_coregroup_map(i);
+ cpus_and(sd->span, sd->span, *cpu_map);
+ sd->parent = p;
+ sd->groups = &sched_group_core[group];
+#endif
+
#ifdef CONFIG_SCHED_SMT
p = sd;
sd = &per_cpu(cpu_domains, i);
@@ -5701,6 +5732,19 @@ void build_sched_domains(const cpumask_t *cpu_map)
}
#endif
+#ifdef CONFIG_SCHED_MC
+ /* Set up multi-core groups */
+ for_each_cpu_mask(i, *cpu_map) {
+ cpumask_t this_core_map = cpu_coregroup_map(i);
+ cpus_and(this_core_map, this_core_map, *cpu_map);
+ if (i != first_cpu(this_core_map))
+ continue;
+ init_sched_build_groups(sched_group_core, this_core_map,
+ &cpu_to_core_group);
+ }
+#endif
+
+
/* Set up physical groups */
for (i = 0; i < MAX_NUMNODES; i++) {
cpumask_t nodemask = node_to_cpumask(i);
@@ -5797,11 +5841,31 @@ void build_sched_domains(const cpumask_t *cpu_map)
power = SCHED_LOAD_SCALE;
sd->groups->cpu_power = power;
#endif
+#ifdef CONFIG_SCHED_MC
+ sd = &per_cpu(core_domains, i);
+ power = SCHED_LOAD_SCALE + (cpus_weight(sd->groups->cpumask)-1)
+ * SCHED_LOAD_SCALE / 10;
+ sd->groups->cpu_power = power;
+
+ sd = &per_cpu(phys_domains, i);
+ /*
+ * This has to be < 2 * SCHED_LOAD_SCALE
+ * Lets keep it SCHED_LOAD_SCALE, so that
+ * while calculating NUMA group's cpu_power
+ * we can simply do
+ * numa_group->cpu_power += phys_group->cpu_power;
+ *
+ * See "only add power once for each physical pkg"
+ * comment below
+ */
+ sd->groups->cpu_power = SCHED_LOAD_SCALE;
+#else
sd = &per_cpu(phys_domains, i);
power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
(cpus_weight(sd->groups->cpumask)-1) / 10;
sd->groups->cpu_power = power;
+#endif
#ifdef CONFIG_NUMA
sd = &per_cpu(allnodes_domains, i);
@@ -5823,7 +5887,6 @@ void build_sched_domains(const cpumask_t *cpu_map)
next_sg:
for_each_cpu_mask(j, sg->cpumask) {
struct sched_domain *sd;
- int power;
sd = &per_cpu(phys_domains, j);
if (j != first_cpu(sd->groups->cpumask)) {
@@ -5833,10 +5896,8 @@ next_sg:
*/
continue;
}
- power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
- (cpus_weight(sd->groups->cpumask)-1) / 10;
- sg->cpu_power += power;
+ sg->cpu_power += sd->groups->cpu_power;
}
sg = sg->next;
if (sg != sched_group_nodes[i])
@@ -5849,6 +5910,8 @@ next_sg:
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
sd = &per_cpu(cpu_domains, i);
+#elif defined(CONFIG_SCHED_MC)
+ sd = &per_cpu(core_domains, i);
#else
sd = &per_cpu(phys_domains, i);
#endif