Don't migrate cache-hot vCPU

diff -r 633debd7b831 tools/libxc/xc_misc.c
--- a/tools/libxc/xc_misc.c	Tue Mar 03 03:17:57 2009 +0800
+++ b/tools/libxc/xc_misc.c	Tue Mar 03 03:17:59 2009 +0800
@@ -92,6 +92,21 @@ int xc_sched_id(int xc_handle,
         return ret;
 
     *sched_id = sysctl.u.sched_id.sched_id;
+
+    return 0;
+}
+
+int xc_migration_cost(int xc_handle,
+                      uint64_t cost)
+{
+    int ret;
+    DECLARE_SYSCTL;
+
+    sysctl.cmd = XEN_SYSCTL_migration_cost;
+    sysctl.u.migration_cost.cost = cost;
+
+    if ( (ret = do_sysctl(xc_handle, &sysctl)) != 0 )
+        return ret;
 
     return 0;
 }
diff -r 633debd7b831 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h	Tue Mar 03 03:17:57 2009 +0800
+++ b/tools/libxc/xenctrl.h	Tue Mar 03 03:17:59 2009 +0800
@@ -611,6 +611,9 @@ int xc_sched_id(int xc_handle,
 int xc_sched_id(int xc_handle,
                 int *sched_id);
 
+int xc_migration_cost(int xc_handle,
+                      uint64_t cost);
+
 typedef xen_sysctl_cpuinfo_t xc_cpuinfo_t;
 int xc_getcpuinfo(int xc_handle, int max_cpus,
                   xc_cpuinfo_t *info, int *nr_cpus); 
diff -r 633debd7b831 tools/xcutils/Makefile
--- a/tools/xcutils/Makefile	Tue Mar 03 03:17:57 2009 +0800
+++ b/tools/xcutils/Makefile	Tue Mar 03 03:17:59 2009 +0800
@@ -14,7 +14,7 @@ CFLAGS += -Werror
 CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest) $(CFLAGS_libxenstore)
 
-PROGRAMS = xc_restore xc_save readnotes lsevtchn
+PROGRAMS = xc_restore xc_save readnotes lsevtchn migration_cost
 
 LDLIBS   = $(LDFLAGS_libxenctrl) $(LDFLAGS_libxenguest) $(LDFLAGS_libxenstore)
 
diff -r 633debd7b831 tools/xcutils/migration_cost.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xcutils/migration_cost.c	Tue Mar 03 03:17:59 2009 +0800
@@ -0,0 +1,25 @@
+#include <err.h>
+#include <stdlib.h>
+
+#include <xenctrl.h>
+
+int main(int argc, char **argv)
+{
+    int xc_fd, rc;
+    long long cost;
+
+    if (argc != 2)
+        errx(1, "usage: %s cost_in_ns", argv[0]);
+
+    cost = strtoll(argv[1], NULL, 0);
+
+    xc_fd = xc_interface_open();
+    if ( xc_fd < 0 )
+        errx(1, "failed to open control interface");
+
+    rc = xc_migration_cost(xc_fd, cost);
+
+    xc_interface_close(xc_fd);
+
+    return rc;
+}
diff -r 633debd7b831 xen/common/sched_credit.c
--- a/xen/common/sched_credit.c	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/common/sched_credit.c	Wed Mar 04 02:09:47 2009 +0800
@@ -123,7 +123,8 @@
     _MACRO(dom_init)                        \
     _MACRO(dom_destroy)                     \
     _MACRO(vcpu_init)                       \
-    _MACRO(vcpu_destroy)
+    _MACRO(vcpu_destroy)                    \
+    _MACRO(vcpu_hot)
 
 #ifndef NDEBUG
 #define CSCHED_STATS_EXPAND_CHECKS(_MACRO)  \
@@ -404,14 +405,29 @@ __csched_vcpu_check(struct vcpu *vc)
 #define CSCHED_VCPU_CHECK(_vc)
 #endif
 
+uint64_t migration_cost;
+
+static inline int
+__csched_vcpu_is_cache_hot(struct vcpu *v)
+{
+        int hot = (NOW() - v->runstate.state_entry_time) < migration_cost;
+
+        if (hot)
+            CSCHED_STAT_CRANK(vcpu_hot);
+
+	return hot;
+}
+
 static inline int
 __csched_vcpu_is_migrateable(struct vcpu *vc, int dest_cpu)
 {
     /*
-     * Don't pick up work that's in the peer's scheduling tail. Also only pick
-     * up work that's allowed to run on our CPU.
-     */
-    return !vc->is_running && cpu_isset(dest_cpu, vc->cpu_affinity);
+     * Don't pick up work that's in the peer's scheduling tail or hot on
+     * peer PCPU. Only pick up work that's allowed to run on our CPU.
+     */
+    return !vc->is_running &&
+           !__csched_vcpu_is_cache_hot(vc) &&
+           cpu_isset(dest_cpu, vc->cpu_affinity);
 }
 
 static int
@@ -1306,7 +1322,8 @@ csched_dump(void)
            "\tmsecs per tick     = %dms\n"
            "\tcredits per tick   = %d\n"
            "\tticks per tslice   = %d\n"
-           "\tticks per acct     = %d\n",
+           "\tticks per acct     = %d\n"
+           "\tmigration cost     = %"PRIu64"ns\n",
            csched_priv.ncpus,
            csched_priv.master,
            csched_priv.credit,
@@ -1317,7 +1334,8 @@ csched_dump(void)
            CSCHED_MSECS_PER_TICK,
            CSCHED_CREDITS_PER_TICK,
            CSCHED_TICKS_PER_TSLICE,
-           CSCHED_TICKS_PER_ACCT);
+           CSCHED_TICKS_PER_ACCT,
+           migration_cost);
 
     cpumask_scnprintf(idlers_buf, sizeof(idlers_buf), csched_priv.idlers);
     printk("idlers: %s\n", idlers_buf);
diff -r 633debd7b831 xen/common/sysctl.c
--- a/xen/common/sysctl.c	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/common/sysctl.c	Tue Mar 03 03:17:59 2009 +0800
@@ -88,6 +88,19 @@ long do_sysctl(XEN_GUEST_HANDLE(xen_sysc
     }
     break;
 
+    case XEN_SYSCTL_migration_cost:
+    {
+        extern uint64_t migration_cost;
+        ret = xsm_migration_cost();
+        if ( ret )
+            break;
+
+        migration_cost = op->u.migration_cost.cost;
+
+        ret = 0;
+    }
+    break;
+
     case XEN_SYSCTL_getdomaininfolist:
     { 
         struct domain *d;
diff -r 633debd7b831 xen/include/public/sysctl.h
--- a/xen/include/public/sysctl.h	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/include/public/sysctl.h	Tue Mar 03 03:17:59 2009 +0800
@@ -359,6 +359,15 @@ struct xen_sysctl_pm_op {
     };
 };
 
+/* Adjust vCPU migration_cost. */
+#define XEN_SYSCTL_migration_cost      13
+struct xen_sysctl_migration_cost {
+    /* IN variables. */
+    uint64_t cost;
+};
+typedef struct xen_sysctl_migration_cost xen_sysctl_migration_cost_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_migration_cost_t);
+
 struct xen_sysctl {
     uint32_t cmd;
     uint32_t interface_version; /* XEN_SYSCTL_INTERFACE_VERSION */
@@ -375,6 +384,7 @@ struct xen_sysctl {
         struct xen_sysctl_get_pmstat        get_pmstat;
         struct xen_sysctl_cpu_hotplug       cpu_hotplug;
         struct xen_sysctl_pm_op             pm_op;
+        struct xen_sysctl_migration_cost    migration_cost;
         uint8_t                             pad[128];
     } u;
 };
diff -r 633debd7b831 xen/include/xsm/xsm.h
--- a/xen/include/xsm/xsm.h	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/include/xsm/xsm.h	Tue Mar 03 03:17:59 2009 +0800
@@ -68,6 +68,7 @@ struct xsm_operations {
     int (*tbufcontrol) (void);
     int (*readconsole) (uint32_t clear);
     int (*sched_id) (void);
+    int (*migration_cost) (void);
     int (*setdomainmaxmem) (struct domain *d);
     int (*setdomainhandle) (struct domain *d);
     int (*setdebugging) (struct domain *d);
@@ -247,6 +248,11 @@ static inline int xsm_sched_id (void)
     return xsm_call(sched_id());
 }
 
+static inline int xsm_migration_cost (void)
+{
+    return xsm_call(migration_cost());
+}
+
 static inline int xsm_setdomainmaxmem (struct domain *d)
 {
     return xsm_call(setdomainmaxmem(d));
diff -r 633debd7b831 xen/xsm/dummy.c
--- a/xen/xsm/dummy.c	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/xsm/dummy.c	Tue Mar 03 03:17:59 2009 +0800
@@ -100,6 +100,11 @@ static int dummy_readconsole (uint32_t c
 }
 
 static int dummy_sched_id (void)
+{
+    return 0;
+}
+
+static int dummy_migration_cost (void)
 {
     return 0;
 }
@@ -486,6 +491,7 @@ void xsm_fixup_ops (struct xsm_operation
     set_to_dummy_if_null(ops, tbufcontrol);
     set_to_dummy_if_null(ops, readconsole);
     set_to_dummy_if_null(ops, sched_id);
+    set_to_dummy_if_null(ops, migration_cost);
     set_to_dummy_if_null(ops, setdomainmaxmem);
     set_to_dummy_if_null(ops, setdomainhandle);
     set_to_dummy_if_null(ops, setdebugging);
diff -r 633debd7b831 xen/xsm/flask/hooks.c
--- a/xen/xsm/flask/hooks.c	Tue Mar 03 03:17:57 2009 +0800
+++ b/xen/xsm/flask/hooks.c	Tue Mar 03 03:17:59 2009 +0800
@@ -597,6 +597,11 @@ static int flask_readconsole(uint32_t cl
 }
 
 static int flask_sched_id(void)
+{
+    return domain_has_xen(current->domain, XEN__SCHEDULER);
+}
+
+static int flask_migration_cost(void)
 {
     return domain_has_xen(current->domain, XEN__SCHEDULER);
 }
@@ -1235,6 +1240,7 @@ static struct xsm_operations flask_ops =
     .tbufcontrol = flask_tbufcontrol,
     .readconsole = flask_readconsole,
     .sched_id = flask_sched_id,
+    .migration_cost = flask_migration_cost,
     .setdomainmaxmem = flask_setdomainmaxmem,
     .setdomainhandle = flask_setdomainhandle,
     .setdebugging = flask_setdebugging,