On 03/16/2010 07:27 AM, Zhang, Yanmin wrote:
From: Zhang, Yanmin<yanmin_zhang@xxxxxxxxxxxxxxx>
Based on the discussion in KVM community, I worked out the patch to support
perf to collect guest os statistics from host side. This patch is implemented
with Ingo, Peter and some other guys' kind help. Yang Sheng pointed out a
critical bug and provided good suggestions with other guys. I really appreciate
their kind help.
The patch adds new subcommand kvm to perf.
perf kvm top
perf kvm record
perf kvm report
perf kvm diff
The new perf could profile guest os kernel except guest os user space, but it
could summarize guest os user space utilization per guest os.
Below are some examples.
1) perf kvm top
[root@lkp-ne01 norm]# perf kvm --host --guest --guestkallsyms=/home/ymzhang/guest/kallsyms
--guestmodules=/home/ymzhang/guest/modules top
Excellent, support for guest kernel != host kernel is critical (I can't
remember the last time I ran same kernels).
How would we support multiple guests with different kernels? Perhaps a
symbol server that perf can connect to (and that would connect to guests
in turn)?
diff -Nraup linux-2.6_tipmaster0315/arch/x86/kvm/vmx.c linux-2.6_tipmaster0315_perfkvm/arch/x86/kvm/vmx.c
--- linux-2.6_tipmaster0315/arch/x86/kvm/vmx.c 2010-03-16 08:59:11.825295404 +0800
+++ linux-2.6_tipmaster0315_perfkvm/arch/x86/kvm/vmx.c 2010-03-16 09:01:09.976084492 +0800
@@ -26,6 +26,7 @@
#include<linux/sched.h>
#include<linux/moduleparam.h>
#include<linux/ftrace_event.h>
+#include<linux/perf_event.h>
#include "kvm_cache_regs.h"
#include "x86.h"
@@ -3632,6 +3633,43 @@ static void update_cr8_intercept(struct
vmcs_write32(TPR_THRESHOLD, irr);
}
+DEFINE_PER_CPU(int, kvm_in_guest) = {0};
+
+static void kvm_set_in_guest(void)
+{
+ percpu_write(kvm_in_guest, 1);
+}
+
+static int kvm_is_in_guest(void)
+{
+ return percpu_read(kvm_in_guest);
+}
There is already PF_VCPU for this.
+static struct perf_guest_info_callbacks kvm_guest_cbs = {
+ .is_in_guest = kvm_is_in_guest,
+ .is_user_mode = kvm_is_user_mode,
+ .get_guest_ip = kvm_get_guest_ip,
+ .reset_in_guest = kvm_reset_in_guest,
+};
Should be in common code, not vmx specific.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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