lkml.org 
[lkml]   [2004]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] Create cpu_sibling_map for PPC64
From
Date
In light of some proposed changes in the sched_domains code, I coded up
this little ditty that simply creates and populates a cpu_sibling_map
for PPC64 machines. The patch just checks the CPU flags to determine if
the CPU supports SMT (aka Hyper-Threading aka Multi-Threading aka ...)
and fills in a mask of the siblings for each CPU in the system. This
should allow us to build sched_domains for PPC64 with generic code in
kernel/sched.c for the SMT systems. SMT is becoming more popular and is
turning up in more and more architectures. I don't think it will be too
long until this feature is supported by most arches...

[mcd@arrakis source]$ diffstat
~/linux/patches/ppc64-cpu_sibling_map.patch
arch/ppc64/kernel/smp.c | 7 +++++++
include/asm-ppc64/smp.h | 1 +
2 files changed, 8 insertions(+)

Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>

-Matt


diff -Nurp --exclude-from=/home/mcd/.dontdiff linux-2.6.8-rc2-mm1/arch/ppc64/kernel/smp.c linux-2.6.8-rc2-mm1+ppc64-cpu_sibling_map/arch/ppc64/kernel/smp.c
--- linux-2.6.8-rc2-mm1/arch/ppc64/kernel/smp.c 2004-07-28 10:50:29.000000000 -0700
+++ linux-2.6.8-rc2-mm1+ppc64-cpu_sibling_map/arch/ppc64/kernel/smp.c 2004-07-28 12:02:38.000000000 -0700
@@ -64,6 +64,7 @@ cpumask_t cpu_possible_map = CPU_MASK_NO
cpumask_t cpu_online_map = CPU_MASK_NONE;
cpumask_t cpu_available_map = CPU_MASK_NONE;
cpumask_t cpu_present_at_boot = CPU_MASK_NONE;
+cpumask_t cpu_sibling_map[NR_CPUS] = { [0 .. NR_CPUS-1] = CPU_MASK_NONE };

EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);
@@ -870,6 +871,12 @@ void __init smp_prepare_cpus(unsigned in
for_each_cpu(cpu)
if (cpu != boot_cpuid)
smp_create_idle(cpu);
+
+ for_each_cpu(cpu) {
+ cpu_set(cpu, cpu_sibling_map[cpu]);
+ if (cur_cpu_spec->cpu_features & CPU_FTR_SMT)
+ cpu_set(cpu ^ 0x1, cpu_sibling_map[cpu]);
+ }
}

void __devinit smp_prepare_boot_cpu(void)
diff -Nurp --exclude-from=/home/mcd/.dontdiff linux-2.6.8-rc2-mm1/include/asm-ppc64/smp.h linux-2.6.8-rc2-mm1+ppc64-cpu_sibling_map/include/asm-ppc64/smp.h
--- linux-2.6.8-rc2-mm1/include/asm-ppc64/smp.h 2004-07-28 10:50:50.000000000 -0700
+++ linux-2.6.8-rc2-mm1+ppc64-cpu_sibling_map/include/asm-ppc64/smp.h 2004-07-28 12:02:38.000000000 -0700
@@ -49,6 +49,7 @@ extern cpumask_t cpu_present_at_boot;
extern cpumask_t cpu_online_map;
extern cpumask_t cpu_possible_map;
extern cpumask_t cpu_available_map;
+extern cpumask_t cpu_sibling_map[NR_CPUS];

#define cpu_present_at_boot(cpu) cpu_isset(cpu, cpu_present_at_boot)
#define cpu_available(cpu) cpu_isset(cpu, cpu_available_map)

-
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/

\
 
 \ /
  Last update: 2005-03-22 14:04    [W:0.083 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site