[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>
diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h
index 8c8d88c..1aa2cee 100644
--- a/include/asm-x86_64/processor.h
+++ b/include/asm-x86_64/processor.h
@@ -20,6 +20,7 @@
#include <asm/mmsegment.h>
#include <asm/percpu.h>
#include <linux/personality.h>
+#include <linux/cpumask.h>
#define TF_MASK 0x00000100
#define IF_MASK 0x00000200
@@ -65,6 +66,9 @@
__u32 x86_power;
__u32 extended_cpuid_level; /* Max extended CPUID function supported */
unsigned long loops_per_jiffy;
+#ifdef CONFIG_SMP
+ cpumask_t llc_shared_map; /* cpus sharing the last level cache */
+#endif
__u8 apicid;
__u8 booted_cores; /* number of cores as seen by OS */
} ____cacheline_aligned;