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[Xen-changelog] [xen-unstable] xenpm: Add a small scheduler knob "sched_smt_power_savings"



# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1237539587 0
# Node ID e5bed83d5180a37126ae60c3e7a43a5aff382b69
# Parent  58610023919b0bd5d84b8ff2550a6dac78bad41a
xenpm: Add a small scheduler knob "sched_smt_power_savings"

Current scheduler only care performance, thus always picks pCPU from
the most idle package. This knob provides another option to pick pCPU from
least idle package, for user who want performance power balance.

Signed-off-by: Yu Ke <ke.yu@xxxxxxxxx>
Signed-off-by: Tian Kevin <kevin.tian@xxxxxxxxx>
---
 tools/libxc/xc_pm.c         |   17 +++++++++++++++++
 tools/libxc/xenctrl.h       |    2 ++
 tools/misc/xenpm.c          |   32 ++++++++++++++++++++++++++++++++
 xen/common/sched_credit.c   |    7 +++++--
 xen/common/schedule.c       |    9 +++++++++
 xen/drivers/acpi/pmstat.c   |   11 +++++++++++
 xen/include/public/sysctl.h |   10 ++++++----
 xen/include/xen/sched.h     |    2 ++
 8 files changed, 84 insertions(+), 6 deletions(-)

diff -r 58610023919b -r e5bed83d5180 tools/libxc/xc_pm.c
--- a/tools/libxc/xc_pm.c       Fri Mar 20 08:57:45 2009 +0000
+++ b/tools/libxc/xc_pm.c       Fri Mar 20 08:59:47 2009 +0000
@@ -345,3 +345,20 @@ int xc_get_cputopo(int xc_handle, struct
     return rc;
 }
 
+/* value:   0 - disable sched_smt_power_savings 
+            1 - enable sched_smt_power_savings
+ */
+int xc_set_sched_opt_smt(int xc_handle, uint32_t value)
+{
+   int rc;
+   DECLARE_SYSCTL;
+
+   sysctl.cmd = XEN_SYSCTL_pm_op;
+   sysctl.u.pm_op.cmd = XEN_SYSCTL_pm_op_set_sched_opt_smt;
+   sysctl.u.pm_op.cpuid = 0;
+   sysctl.u.pm_op.set_sched_opt_smt = value;
+   rc = do_sysctl(xc_handle, &sysctl);
+
+   return rc;
+}
+
diff -r 58610023919b -r e5bed83d5180 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h     Fri Mar 20 08:57:45 2009 +0000
+++ b/tools/libxc/xenctrl.h     Fri Mar 20 08:59:47 2009 +0000
@@ -1260,4 +1260,6 @@ struct xc_get_cputopo {
 
 int xc_get_cputopo(int xc_handle, struct xc_get_cputopo *info);
 
+int xc_set_sched_opt_smt(int xc_handle, uint32_t value);
+
 #endif /* XENCTRL_H */
diff -r 58610023919b -r e5bed83d5180 tools/misc/xenpm.c
--- a/tools/misc/xenpm.c        Fri Mar 20 08:57:45 2009 +0000
+++ b/tools/misc/xenpm.c        Fri Mar 20 08:59:47 2009 +0000
@@ -56,6 +56,7 @@ void show_help(void)
             " set-up-threshold      [cpuid] <num> set up threshold on CPU 
<cpuid> or all\n"
             "                                     it is used in ondemand 
governor.\n"
             " get-cpu-topology                    get thread/core/socket 
topology info\n"
+            " set-sched-smt           enable|disable enable/disable scheduler 
smt power saving\n"
             " start [seconds]                     start collect Cx/Px 
statistics,\n"
             "                                     output after CTRL-C or 
SIGINT or several seconds.\n"
             );
@@ -838,6 +839,36 @@ void cpu_topology_func(int argc, char *a
     return ;
 }
 
+void set_sched_smt_func(int argc, char *argv[])
+{
+    int value, rc;
+
+    if (argc != 1){
+        show_help();
+        exit(-1);
+    }
+
+    if ( !strncmp(argv[0], "disable", sizeof("disable")) )
+    {
+        value = 0;
+    }
+    else if ( !strncmp(argv[0], "enable", sizeof("enable")) )
+    {
+        value = 1;
+    }
+    else
+    {
+        show_help();
+        exit(-1);
+    }
+
+    rc = xc_set_sched_opt_smt(xc_fd, value);
+    printf("%s sched_smt_power_savings %s\n", argv[0],
+                    rc? "failed":"successeed" );
+
+    return;
+}
+
 struct {
     const char *name;
     void (*function)(int argc, char *argv[]);
@@ -854,6 +885,7 @@ struct {
     { "set-sampling-rate", scaling_sampling_rate_func },
     { "set-up-threshold", scaling_up_threshold_func },
     { "get-cpu-topology", cpu_topology_func},
+    { "set-sched-smt", set_sched_smt_func},
 };
 
 int main(int argc, char *argv[])
diff -r 58610023919b -r e5bed83d5180 xen/common/sched_credit.c
--- a/xen/common/sched_credit.c Fri Mar 20 08:57:45 2009 +0000
+++ b/xen/common/sched_credit.c Fri Mar 20 08:59:47 2009 +0000
@@ -387,7 +387,7 @@ csched_cpu_pick(struct vcpu *vc)
     {
         cpumask_t cpu_idlers;
         cpumask_t nxt_idlers;
-        int nxt;
+        int nxt, weight_cpu, weight_nxt;
 
         nxt = cycle_cpu(cpu, cpus);
 
@@ -404,7 +404,10 @@ csched_cpu_pick(struct vcpu *vc)
             cpus_and(nxt_idlers, idlers, cpu_core_map[nxt]);
         }
 
-        if ( cpus_weight(cpu_idlers) < cpus_weight(nxt_idlers) )
+        weight_cpu = cpus_weight(cpu_idlers);
+        weight_nxt = cpus_weight(nxt_idlers);
+        if ( ( (weight_cpu < weight_nxt) ^ sched_smt_power_savings )
+                && (weight_cpu != weight_nxt) )
         {
             cpu = nxt;
             cpu_clear(cpu, cpus);
diff -r 58610023919b -r e5bed83d5180 xen/common/schedule.c
--- a/xen/common/schedule.c     Fri Mar 20 08:57:45 2009 +0000
+++ b/xen/common/schedule.c     Fri Mar 20 08:59:47 2009 +0000
@@ -38,6 +38,13 @@ static char opt_sched[10] = "credit";
 static char opt_sched[10] = "credit";
 string_param("sched", opt_sched);
 
+/* if sched_smt_power_savings is set,
+ * scheduler will give preferrence to partially idle package compared to
+ * the full idle package, when picking pCPU to schedule vCPU.
+ */
+int sched_smt_power_savings = 0;
+boolean_param("sched_smt_power_savings", sched_smt_power_savings);
+
 #define TIME_SLOP      (s32)MICROSECS(50)     /* allow time to slip a bit */
 
 /* Various timer handlers. */
@@ -942,6 +949,8 @@ void dump_runq(unsigned char key)
 
     printk("Scheduler: %s (%s)\n", ops.name, ops.opt_name);
     SCHED_OP(dump_settings);
+    printk("sched_smt_power_savings: %s\n",
+            sched_smt_power_savings? "enabled":"disabled");
     printk("NOW=0x%08X%08X\n",  (u32)(now>>32), (u32)now);
 
     for_each_online_cpu ( i )
diff -r 58610023919b -r e5bed83d5180 xen/drivers/acpi/pmstat.c
--- a/xen/drivers/acpi/pmstat.c Fri Mar 20 08:57:45 2009 +0000
+++ b/xen/drivers/acpi/pmstat.c Fri Mar 20 08:59:47 2009 +0000
@@ -516,6 +516,17 @@ int do_pm_op(struct xen_sysctl_pm_op *op
         break;
     }
 
+    case XEN_SYSCTL_pm_op_set_sched_opt_smt:
+    {
+        uint32_t saved_value;
+
+        saved_value = sched_smt_power_savings;
+        sched_smt_power_savings = !!op->set_sched_opt_smt;
+        op->set_sched_opt_smt = saved_value;
+
+        break;
+    }
+
     default:
         printk("not defined sub-hypercall @ do_pm_op\n");
         ret = -ENOSYS;
diff -r 58610023919b -r e5bed83d5180 xen/include/public/sysctl.h
--- a/xen/include/public/sysctl.h       Fri Mar 20 08:57:45 2009 +0000
+++ b/xen/include/public/sysctl.h       Fri Mar 20 08:59:47 2009 +0000
@@ -348,11 +348,9 @@ struct xen_set_cpufreq_para {
 
     uint32_t ctrl_type;
     uint32_t ctrl_value;
-}
-;
+};
+
 /* Get physical CPU topology information. */
-
-
 #define INVALID_TOPOLOGY_ID  (~0U)
 struct xen_get_cputopo {
      /* IN: maximum addressable entry in
@@ -381,6 +379,9 @@ struct xen_sysctl_pm_op {
     /* get CPU topology */
     #define XEN_SYSCTL_pm_op_get_cputopo  0x20
 
+    /* set/reset scheduler power saving option */
+    #define XEN_SYSCTL_pm_op_set_sched_opt_smt    0x21
+
     uint32_t cmd;
     uint32_t cpuid;
     union {
@@ -389,6 +390,7 @@ struct xen_sysctl_pm_op {
         struct xen_set_cpufreq_para set_para;
         uint64_t get_avgfreq;
         struct xen_get_cputopo      get_topo;
+        uint32_t                    set_sched_opt_smt;
     };
 };
 
diff -r 58610023919b -r e5bed83d5180 xen/include/xen/sched.h
--- a/xen/include/xen/sched.h   Fri Mar 20 08:57:45 2009 +0000
+++ b/xen/include/xen/sched.h   Fri Mar 20 08:59:47 2009 +0000
@@ -550,6 +550,8 @@ uint64_t get_cpu_idle_time(unsigned int 
 #define is_hvm_vcpu(v)   (is_hvm_domain(v->domain))
 #define need_iommu(d)    ((d)->need_iommu && !(d)->is_hvm)
 
+extern int sched_smt_power_savings;
+
 extern enum cpufreq_controller {
     FREQCTL_none, FREQCTL_dom0_kernel, FREQCTL_xen
 } cpufreq_controller;

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