[S390] Vertical cpu management.
If vertical cpu polarization is active then the hypervisor will
dispatch certain cpus for a longer time than other cpus for maximum
performance. For example if a guest would have three virtual cpus,
each of them with a share of 33 percent, then in case of vertical
cpu polarization all of the processing time would be combined to a
single cpu which would run all the time, while the other two cpus
would get nearly no cpu time.
There are three different types of vertical cpus: high, medium and
low. Low cpus hardly get any real cpu time, while high cpus get a
full real cpu. Medium cpus get something in between.
In order to switch between the two possible modes (default is
horizontal) a 0 for horizontal polarization or a 1 for vertical
polarization must be written to the dispatching sysfs attribute:
/sys/devices/system/cpu/dispatching
The polarization of each single cpu can be figured out by the
polarization sysfs attribute of each cpu:
/sys/devices/system/cpu/cpuX/polarization
horizontal, vertical:high, vertical:medium, vertical:low or unknown.
When switching polarization the polarization attribute may contain
the value unknown until the configuration change is done and the
kernel has figured out the new polarization of each cpu.
Note that running a system with different types of vertical cpus may
result in significant performance regressions. If possible only one
type of vertical cpus should be used. All other cpus should be
offlined.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 5448aa8..d1e8e8a 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -68,7 +68,9 @@
};
DEFINE_MUTEX(smp_cpu_state_mutex);
+int smp_cpu_polarization[NR_CPUS];
static int smp_cpu_state[NR_CPUS];
+static int cpu_management;
static DEFINE_PER_CPU(struct cpu, cpu_devices);
DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
@@ -454,6 +456,7 @@
if (cpu_known(cpu_id))
continue;
__cpu_logical_map[logical_cpu] = cpu_id;
+ smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
if (!cpu_stopped(logical_cpu))
continue;
cpu_set(logical_cpu, cpu_present_map);
@@ -487,6 +490,7 @@
if (cpu_known(cpu_id))
continue;
__cpu_logical_map[logical_cpu] = cpu_id;
+ smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
cpu_set(logical_cpu, cpu_present_map);
if (cpu >= info->configured)
smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
@@ -844,6 +848,7 @@
S390_lowcore.percpu_offset = __per_cpu_offset[0];
current_set[0] = current;
smp_cpu_state[0] = CPU_STATE_CONFIGURED;
+ smp_cpu_polarization[0] = POLARIZATION_UNKNWN;
spin_lock_init(&(&__get_cpu_var(s390_idle))->lock);
}
@@ -895,15 +900,19 @@
case 0:
if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
- if (!rc)
+ if (!rc) {
smp_cpu_state[cpu] = CPU_STATE_STANDBY;
+ smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
+ }
}
break;
case 1:
if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
- if (!rc)
+ if (!rc) {
smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
+ smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
+ }
}
break;
default:
@@ -917,6 +926,34 @@
static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
#endif /* CONFIG_HOTPLUG_CPU */
+static ssize_t cpu_polarization_show(struct sys_device *dev, char *buf)
+{
+ int cpu = dev->id;
+ ssize_t count;
+
+ mutex_lock(&smp_cpu_state_mutex);
+ switch (smp_cpu_polarization[cpu]) {
+ case POLARIZATION_HRZ:
+ count = sprintf(buf, "horizontal\n");
+ break;
+ case POLARIZATION_VL:
+ count = sprintf(buf, "vertical:low\n");
+ break;
+ case POLARIZATION_VM:
+ count = sprintf(buf, "vertical:medium\n");
+ break;
+ case POLARIZATION_VH:
+ count = sprintf(buf, "vertical:high\n");
+ break;
+ default:
+ count = sprintf(buf, "unknown\n");
+ break;
+ }
+ mutex_unlock(&smp_cpu_state_mutex);
+ return count;
+}
+static SYSDEV_ATTR(polarization, 0444, cpu_polarization_show, NULL);
+
static ssize_t show_cpu_address(struct sys_device *dev, char *buf)
{
return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
@@ -929,6 +966,7 @@
&attr_configure.attr,
#endif
&attr_address.attr,
+ &attr_polarization.attr,
NULL,
};
@@ -1073,11 +1111,48 @@
out:
put_online_cpus();
mutex_unlock(&smp_cpu_state_mutex);
+ if (!cpus_empty(newcpus))
+ topology_schedule_update();
return rc ? rc : count;
}
static SYSDEV_ATTR(rescan, 0200, NULL, rescan_store);
#endif /* CONFIG_HOTPLUG_CPU */
+static ssize_t dispatching_show(struct sys_device *dev, char *buf)
+{
+ ssize_t count;
+
+ mutex_lock(&smp_cpu_state_mutex);
+ count = sprintf(buf, "%d\n", cpu_management);
+ mutex_unlock(&smp_cpu_state_mutex);
+ return count;
+}
+
+static ssize_t dispatching_store(struct sys_device *dev, const char *buf,
+ size_t count)
+{
+ int val, rc;
+ char delim;
+
+ if (sscanf(buf, "%d %c", &val, &delim) != 1)
+ return -EINVAL;
+ if (val != 0 && val != 1)
+ return -EINVAL;
+ rc = 0;
+ mutex_lock(&smp_cpu_state_mutex);
+ get_online_cpus();
+ if (cpu_management == val)
+ goto out;
+ rc = topology_set_cpu_management(val);
+ if (!rc)
+ cpu_management = val;
+out:
+ put_online_cpus();
+ mutex_unlock(&smp_cpu_state_mutex);
+ return rc ? rc : count;
+}
+static SYSDEV_ATTR(dispatching, 0644, dispatching_show, dispatching_store);
+
static int __init topology_init(void)
{
int cpu;
@@ -1091,6 +1166,10 @@
if (rc)
return rc;
#endif
+ rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
+ &attr_dispatching.attr);
+ if (rc)
+ return rc;
for_each_present_cpu(cpu) {
rc = smp_add_present_cpu(cpu);
if (rc)
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 369dc1c..12b39b3 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -1,6 +1,4 @@
/*
- * arch/s390/kernel/topology.c
- *
* Copyright IBM Corp. 2007
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
@@ -19,9 +17,17 @@
#include <asm/sysinfo.h>
#define CPU_BITS 64
+#define NR_MAG 6
+
+#define PTF_HORIZONTAL (0UL)
+#define PTF_VERTICAL (1UL)
+#define PTF_CHECK (2UL)
struct tl_cpu {
- unsigned char reserved[6];
+ unsigned char reserved0[4];
+ unsigned char :6;
+ unsigned char pp:2;
+ unsigned char reserved1;
unsigned short origin;
unsigned long mask[CPU_BITS / BITS_PER_LONG];
};
@@ -36,8 +42,6 @@
struct tl_container container;
};
-#define NR_MAG 6
-
struct tl_info {
unsigned char reserved0[2];
unsigned short length;
@@ -96,8 +100,10 @@
rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
for_each_present_cpu(lcpu) {
- if (__cpu_logical_map[lcpu] == rcpu)
+ if (__cpu_logical_map[lcpu] == rcpu) {
cpu_set(lcpu, core->mask);
+ smp_cpu_polarization[lcpu] = tl_cpu->pp;
+ }
}
}
}
@@ -127,7 +133,7 @@
mutex_lock(&smp_cpu_state_mutex);
clear_cores();
- tle = (union tl_entry *)&info->tle;
+ tle = info->tle;
end = (union tl_entry *)((unsigned long)info + info->length);
while (tle < end) {
switch (tle->nl) {
@@ -152,7 +158,17 @@
mutex_unlock(&smp_cpu_state_mutex);
}
-static int ptf(void)
+static void topology_update_polarization_simple(void)
+{
+ int cpu;
+
+ mutex_lock(&smp_cpu_state_mutex);
+ for_each_present_cpu(cpu)
+ smp_cpu_polarization[cpu] = POLARIZATION_HRZ;
+ mutex_unlock(&smp_cpu_state_mutex);
+}
+
+static int ptf(unsigned long fc)
{
int rc;
@@ -161,7 +177,25 @@
" ipm %0\n"
" srl %0,28\n"
: "=d" (rc)
- : "d" (2UL) : "cc");
+ : "d" (fc) : "cc");
+ return rc;
+}
+
+int topology_set_cpu_management(int fc)
+{
+ int cpu;
+ int rc;
+
+ if (!machine_has_topology)
+ return -EOPNOTSUPP;
+ if (fc)
+ rc = ptf(PTF_VERTICAL);
+ else
+ rc = ptf(PTF_HORIZONTAL);
+ if (rc)
+ return -EBUSY;
+ for_each_present_cpu(cpu)
+ smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
return rc;
}
@@ -171,9 +205,10 @@
struct sys_device *sysdev;
int cpu;
- if (!machine_has_topology)
+ if (!machine_has_topology) {
+ topology_update_polarization_simple();
return;
- ptf();
+ }
stsi(info, 15, 1, 2);
tl_to_cores(info);
for_each_online_cpu(cpu) {
@@ -187,10 +222,15 @@
arch_reinit_sched_domains();
}
+void topology_schedule_update(void)
+{
+ schedule_work(&topology_work);
+}
+
static void topology_timer_fn(unsigned long ignored)
{
- if (ptf())
- schedule_work(&topology_work);
+ if (ptf(PTF_CHECK))
+ topology_schedule_update();
set_topology_timer();
}
@@ -211,9 +251,11 @@
{
int rc;
- if (!machine_has_topology)
+ if (!machine_has_topology) {
+ topology_update_polarization_simple();
return 0;
- init_timer(&topology_timer);
+ }
+ init_timer_deferrable(&topology_timer);
if (machine_has_topology_irq) {
rc = register_external_interrupt(0x2005, topology_interrupt);
if (rc)
diff --git a/include/asm-s390/smp.h b/include/asm-s390/smp.h
index a464a66..6f3821a 100644
--- a/include/asm-s390/smp.h
+++ b/include/asm-s390/smp.h
@@ -91,6 +91,7 @@
extern int __cpu_up (unsigned int cpu);
extern struct mutex smp_cpu_state_mutex;
+extern int smp_cpu_polarization[];
extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
void *info, int wait);
diff --git a/include/asm-s390/topology.h b/include/asm-s390/topology.h
index 3b28a09..8e97b06 100644
--- a/include/asm-s390/topology.h
+++ b/include/asm-s390/topology.h
@@ -7,6 +7,15 @@
cpumask_t cpu_coregroup_map(unsigned int cpu);
+int topology_set_cpu_management(int fc);
+void topology_schedule_update(void);
+
+#define POLARIZATION_UNKNWN (-1)
+#define POLARIZATION_HRZ (0)
+#define POLARIZATION_VL (1)
+#define POLARIZATION_VM (2)
+#define POLARIZATION_VH (3)
+
#ifdef CONFIG_SMP
void s390_init_cpu_topology(void);
#else