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authorAtish Patra <atish.patra@oracle.com>2016-10-19 18:33:29 -0600
committerDavid S. Miller <davem@davemloft.net>2016-10-24 11:04:17 -0700
commitd624716b6c67e60681180786564b92ddb521148a (patch)
tree515fe225d781a617412e64dfa36aa1056cf9bd25
parent07d9a380680d1c0eb51ef87ff2eab5c994949e69 (diff)
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sparc64: Setup a scheduling domain for highest level cache.
Individual scheduler domain should consist different hierarchy consisting of cores sharing similar property. Currently, no scheduler domain is defined separately for the cores that shares the last level cache. As a result, the scheduler fails to take advantage of cache locality while migrating tasks during load balancing. Here are the cpu masks currently present for sparc that are/can be used in scheduler domain construction. cpu_core_map : set based on the cores that shares l1 cache. core_core_sib_map : is set based on the socket id. The prior SPARC notion of socket was defined as highest level of shared cache. However, the MD record on T7 platforms now describes the CPUs that share the physical socket and this is no longer tied to shared cache. That's why a separate cpu mask needs to be created that truly represent highest level of shared cache for all platforms. Signed-off-by: Atish Patra <atish.patra@oracle.com> Reviewed-by: Chris Hyser <chris.hyser@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc/include/asm/cpudata_64.h5
-rw-r--r--arch/sparc/include/asm/topology_64.h8
-rw-r--r--arch/sparc/kernel/mdesc.c46
-rw-r--r--arch/sparc/kernel/smp_64.c8
4 files changed, 46 insertions, 21 deletions
diff --git a/arch/sparc/include/asm/cpudata_64.h b/arch/sparc/include/asm/cpudata_64.h
index a6cfdabb6054..5b0ed48e5b0c 100644
--- a/arch/sparc/include/asm/cpudata_64.h
+++ b/arch/sparc/include/asm/cpudata_64.h
@@ -24,9 +24,10 @@ typedef struct {
unsigned int icache_line_size;
unsigned int ecache_size;
unsigned int ecache_line_size;
- unsigned short sock_id;
+ unsigned short sock_id; /* physical package */
unsigned short core_id;
- int proc_id;
+ unsigned short max_cache_id; /* groupings of highest shared cache */
+ unsigned short proc_id; /* strand (aka HW thread) id */
} cpuinfo_sparc;
DECLARE_PER_CPU(cpuinfo_sparc, __cpu_data);
diff --git a/arch/sparc/include/asm/topology_64.h b/arch/sparc/include/asm/topology_64.h
index bec481aaca16..7b4898a36eee 100644
--- a/arch/sparc/include/asm/topology_64.h
+++ b/arch/sparc/include/asm/topology_64.h
@@ -44,14 +44,20 @@ int __node_distance(int, int);
#define topology_physical_package_id(cpu) (cpu_data(cpu).proc_id)
#define topology_core_id(cpu) (cpu_data(cpu).core_id)
#define topology_core_cpumask(cpu) (&cpu_core_sib_map[cpu])
+#define topology_core_cache_cpumask(cpu) (&cpu_core_sib_cache_map[cpu])
#define topology_sibling_cpumask(cpu) (&per_cpu(cpu_sibling_map, cpu))
#endif /* CONFIG_SMP */
extern cpumask_t cpu_core_map[NR_CPUS];
extern cpumask_t cpu_core_sib_map[NR_CPUS];
+extern cpumask_t cpu_core_sib_cache_map[NR_CPUS];
+
+/**
+ * Return cores that shares the last level cache.
+ */
static inline const struct cpumask *cpu_coregroup_mask(int cpu)
{
- return &cpu_core_map[cpu];
+ return &cpu_core_sib_cache_map[cpu];
}
#endif /* _ASM_SPARC64_TOPOLOGY_H */
diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c
index 11228861d9b4..8a6982dfd733 100644
--- a/arch/sparc/kernel/mdesc.c
+++ b/arch/sparc/kernel/mdesc.c
@@ -645,13 +645,20 @@ static void __mark_core_id(struct mdesc_handle *hp, u64 node,
cpu_data(*id).core_id = core_id;
}
-static void __mark_sock_id(struct mdesc_handle *hp, u64 node,
- int sock_id)
+static void __mark_max_cache_id(struct mdesc_handle *hp, u64 node,
+ int max_cache_id)
{
const u64 *id = mdesc_get_property(hp, node, "id", NULL);
- if (*id < num_possible_cpus())
- cpu_data(*id).sock_id = sock_id;
+ if (*id < num_possible_cpus()) {
+ cpu_data(*id).max_cache_id = max_cache_id;
+
+ /**
+ * On systems without explicit socket descriptions socket
+ * is max_cache_id
+ */
+ cpu_data(*id).sock_id = max_cache_id;
+ }
}
static void mark_core_ids(struct mdesc_handle *hp, u64 mp,
@@ -660,10 +667,11 @@ static void mark_core_ids(struct mdesc_handle *hp, u64 mp,
find_back_node_value(hp, mp, "cpu", __mark_core_id, core_id, 10);
}
-static void mark_sock_ids(struct mdesc_handle *hp, u64 mp,
- int sock_id)
+static void mark_max_cache_ids(struct mdesc_handle *hp, u64 mp,
+ int max_cache_id)
{
- find_back_node_value(hp, mp, "cpu", __mark_sock_id, sock_id, 10);
+ find_back_node_value(hp, mp, "cpu", __mark_max_cache_id,
+ max_cache_id, 10);
}
static void set_core_ids(struct mdesc_handle *hp)
@@ -694,14 +702,15 @@ static void set_core_ids(struct mdesc_handle *hp)
}
}
-static int set_sock_ids_by_cache(struct mdesc_handle *hp, int level)
+static int set_max_cache_ids_by_cache(struct mdesc_handle *hp, int level)
{
u64 mp;
int idx = 1;
int fnd = 0;
- /* Identify unique sockets by looking for cpus backpointed to by
- * shared level n caches.
+ /**
+ * Identify unique highest level of shared cache by looking for cpus
+ * backpointed to by shared level N caches.
*/
mdesc_for_each_node_by_name(hp, mp, "cache") {
const u64 *cur_lvl;
@@ -709,8 +718,7 @@ static int set_sock_ids_by_cache(struct mdesc_handle *hp, int level)
cur_lvl = mdesc_get_property(hp, mp, "level", NULL);
if (*cur_lvl != level)
continue;
-
- mark_sock_ids(hp, mp, idx);
+ mark_max_cache_ids(hp, mp, idx);
idx++;
fnd = 1;
}
@@ -745,15 +753,17 @@ static void set_sock_ids(struct mdesc_handle *hp)
{
u64 mp;
- /* If machine description exposes sockets data use it.
- * Otherwise fallback to use shared L3 or L2 caches.
+ /**
+ * Find the highest level of shared cache which pre-T7 is also
+ * the socket.
*/
+ if (!set_max_cache_ids_by_cache(hp, 3))
+ set_max_cache_ids_by_cache(hp, 2);
+
+ /* If machine description exposes sockets data use it.*/
mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "sockets");
if (mp != MDESC_NODE_NULL)
- return set_sock_ids_by_socket(hp, mp);
-
- if (!set_sock_ids_by_cache(hp, 3))
- set_sock_ids_by_cache(hp, 2);
+ set_sock_ids_by_socket(hp, mp);
}
static void mark_proc_ids(struct mdesc_handle *hp, u64 mp, int proc_id)
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index d3035ba6cd31..8182f7caf5b1 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -63,9 +63,13 @@ cpumask_t cpu_core_map[NR_CPUS] __read_mostly =
cpumask_t cpu_core_sib_map[NR_CPUS] __read_mostly = {
[0 ... NR_CPUS-1] = CPU_MASK_NONE };
+cpumask_t cpu_core_sib_cache_map[NR_CPUS] __read_mostly = {
+ [0 ... NR_CPUS - 1] = CPU_MASK_NONE };
+
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_SYMBOL(cpu_core_map);
EXPORT_SYMBOL(cpu_core_sib_map);
+EXPORT_SYMBOL(cpu_core_sib_cache_map);
static cpumask_t smp_commenced_mask;
@@ -1265,6 +1269,10 @@ void smp_fill_in_sib_core_maps(void)
unsigned int j;
for_each_present_cpu(j) {
+ if (cpu_data(i).max_cache_id ==
+ cpu_data(j).max_cache_id)
+ cpumask_set_cpu(j, &cpu_core_sib_cache_map[i]);
+
if (cpu_data(i).sock_id == cpu_data(j).sock_id)
cpumask_set_cpu(j, &cpu_core_sib_map[i]);
}