[PATCH] KVM: add VM-exit profiling

This adds the profile=kvm boot option, which enables KVM to profile VM
exits.

Use: "readprofile -m ./System.map | sort -n" to see the resulting
output:

   [...]
   18246 serial_out                               148.3415
   18945 native_flush_tlb                         378.9000
   23618 serial_in                                212.7748
   29279 __spin_unlock_irq                        622.9574
   43447 native_apic_write                        2068.9048
   52702 enable_8259A_irq                         742.2817
   54250 vgacon_scroll                             89.3740
   67394 ide_inb                                  6126.7273
   79514 copy_page_range                           98.1654
   84868 do_wp_page                                86.6000
  140266 pit_read                                 783.6089
  151436 ide_outb                                 25239.3333
  152668 native_io_delay                          21809.7143
  174783 mask_and_ack_8259A                       783.7803
  362404 native_set_pte_at                        36240.4000
 1688747 total                                      0.5009

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/profile.c b/kernel/profile.c
index 11550b2290b6..a6574a18514e 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -40,7 +40,10 @@ int (*timer_hook)(struct pt_regs *) __read_mostly;
 
 static atomic_t *prof_buffer;
 static unsigned long prof_len, prof_shift;
+
 int prof_on __read_mostly;
+EXPORT_SYMBOL_GPL(prof_on);
+
 static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
 #ifdef CONFIG_SMP
 static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
@@ -52,6 +55,7 @@ static int __init profile_setup(char * str)
 {
         static char __initdata schedstr[] = "schedule";
         static char __initdata sleepstr[] = "sleep";
+        static char __initdata kvmstr[] = "kvm";
         int par;
 
         if (!strncmp(str, sleepstr, strlen(sleepstr))) {
@@ -72,6 +76,15 @@ static int __init profile_setup(char * str)
                 printk(KERN_INFO
                         "kernel schedule profiling enabled (shift: %ld)\n",
                         prof_shift);
+        } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
+                prof_on = KVM_PROFILING;
+                if (str[strlen(kvmstr)] == ',')
+                        str += strlen(kvmstr) + 1;
+                if (get_option(&str, &par))
+                        prof_shift = par;
+                printk(KERN_INFO
+                        "kernel KVM profiling enabled (shift: %ld)\n",
+                        prof_shift);
         } else if (get_option(&str, &par)) {
                 prof_shift = par;
                 prof_on = CPU_PROFILING;
@@ -318,6 +331,7 @@ out:
         local_irq_restore(flags);
         put_cpu();
 }
+EXPORT_SYMBOL_GPL(profile_hits);
 
 static int __devinit profile_cpu_callback(struct notifier_block *info,
                                         unsigned long action, void *__cpu)