[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>
diff --git a/kernel/profile.c b/kernel/profile.c
index 11550b2..a6574a1 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -40,7 +40,10 @@
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 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 @@
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 @@
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)