# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 68915c4893ee3184ca955b90e221dd8e69772a46
# Parent 2625000d314588d0844b7a7a89be9887881cd5d8
Add a 't' debug key to Xen for displaying info about cross-cpu clock jitter.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
diff -r 2625000d3145 -r 68915c4893ee xen/common/keyhandler.c
--- a/xen/common/keyhandler.c Mon Mar 13 12:03:18 2006
+++ b/xen/common/keyhandler.c Mon Mar 13 12:03:51 2006
@@ -14,6 +14,7 @@
#include <xen/rangeset.h>
#include <asm/debugger.h>
#include <asm/shadow.h>
+#include <asm/div64.h>
#define KEY_MAX 256
#define STR_MAX 64
@@ -168,6 +169,58 @@
read_unlock(&domlist_lock);
}
+static cpumask_t read_clocks_cpumask = CPU_MASK_NONE;
+static s_time_t read_clocks_time[NR_CPUS];
+
+static void read_clocks_slave(void *unused)
+{
+ unsigned int cpu = smp_processor_id();
+ while ( !cpu_isset(cpu, read_clocks_cpumask) )
+ cpu_relax();
+ read_clocks_time[cpu] = NOW();
+ cpu_clear(cpu, read_clocks_cpumask);
+}
+
+static void read_clocks(unsigned char key)
+{
+ unsigned int cpu = smp_processor_id(), min_cpu, max_cpu;
+ u64 min, max, dif, difus;
+ static DEFINE_SPINLOCK(lock);
+
+ spin_lock(&lock);
+
+ smp_call_function(read_clocks_slave, NULL, 0, 0);
+
+ local_irq_disable();
+ read_clocks_cpumask = cpu_online_map;
+ read_clocks_time[cpu] = NOW();
+ cpu_clear(cpu, read_clocks_cpumask);
+ local_irq_enable();
+
+ while ( !cpus_empty(read_clocks_cpumask) )
+ cpu_relax();
+
+ min_cpu = max_cpu = cpu;
+ for_each_online_cpu ( cpu )
+ {
+ if ( read_clocks_time[cpu] < read_clocks_time[min_cpu] )
+ min_cpu = cpu;
+ if ( read_clocks_time[cpu] > read_clocks_time[max_cpu] )
+ max_cpu = cpu;
+ }
+
+ min = read_clocks_time[min_cpu];
+ max = read_clocks_time[max_cpu];
+
+ spin_unlock(&lock);
+
+ dif = difus = max - min;
+ do_div(difus, 1000);
+ printk("Min = %"PRIu64" ; Max = %"PRIu64" ; Diff = %"PRIu64
+ " (%"PRIu64" microseconds)\n",
+ min, max, dif, difus);
+}
+
extern void dump_runq(unsigned char key);
#ifndef NDEBUG
extern void audit_domains_key(unsigned char key);
@@ -178,7 +231,7 @@
extern void perfc_reset(unsigned char key);
#endif
-void do_debug_key(unsigned char key, struct cpu_user_regs *regs)
+static void do_debug_key(unsigned char key, struct cpu_user_regs *regs)
{
(void)debugger_trap_fatal(0xf001, regs);
nop(); /* Prevent the compiler doing tail call
@@ -187,7 +240,7 @@
}
#ifndef NDEBUG
-void debugtrace_key(unsigned char key)
+static void debugtrace_key(unsigned char key)
{
debugtrace_send_to_console = !debugtrace_send_to_console;
debugtrace_dump();
@@ -210,6 +263,9 @@
'r', dump_runq, "dump run queues");
register_irq_keyhandler(
'R', halt_machine, "reboot machine");
+
+ register_keyhandler(
+ 't', read_clocks, "display multi-cpu clock info");
#ifndef NDEBUG
register_keyhandler(
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