Messages in this thread Patch in this message | | | Subject | [patch] Export Last Level Cache topology to userspace | From | Arjan van de Ven <> | Date | Sun, 19 Nov 2006 12:15:20 +0100 |
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Hi,
right now the sysfs topology information exports things like sibling maps (which cpu is a hyperthreading peer of another) and which "linux cpus" share the physical package. The patch below adds a bitmap in the same style that exports which "linux cpus" share the last level cache. This is relevant at least for the current line of Intel Quad cores (but also for AMD's dual core offering) where the biggest cache isn't shared on the package level, but only be some cores (Intel) or only one core (AMD).
This information is useful for userspace that wants to do explicit process placement, and in specific, I'm going to need it in the irqbalance rewrite (which is going to balance irqs on the cache domain level).
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Index: linux-2.6.19-rc6/drivers/base/topology.c =================================================================== --- linux-2.6.19-rc6.orig/drivers/base/topology.c +++ linux-2.6.19-rc6/drivers/base/topology.c @@ -81,11 +81,20 @@ define_one_ro(core_siblings); #define ref_core_siblings_attr #endif +#ifdef topology_llc_siblings +define_siblings_show_func(llc_siblings); +define_one_ro(llc_siblings); +#define ref_llc_siblings_attr &attr_llc_siblings.attr, +#else +#define ref_llc_siblings_attr +#endif + static struct attribute *default_attrs[] = { ref_physical_package_id_attr ref_core_id_attr ref_thread_siblings_attr ref_core_siblings_attr + ref_llc_siblings_attr NULL }; Index: linux-2.6.19-rc6/include/asm-x86_64/topology.h =================================================================== --- linux-2.6.19-rc6.orig/include/asm-x86_64/topology.h +++ linux-2.6.19-rc6/include/asm-x86_64/topology.h @@ -60,6 +60,7 @@ extern int __node_distance(int, int); #define topology_core_id(cpu) (cpu_data[cpu].cpu_core_id) #define topology_core_siblings(cpu) (cpu_core_map[cpu]) #define topology_thread_siblings(cpu) (cpu_sibling_map[cpu]) +#define topology_llc_siblings(cpu) (cpu_data[cpu].llc_shared_map) #define mc_capable() (boot_cpu_data.x86_max_cores > 1) #define smt_capable() (smp_num_siblings > 1) #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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