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Date: Mon, 21 Jun 2010 17:31:24 +0800
From: "Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
To: LKML <linux-kernel@...r.kernel.org>, kvm@...r.kernel.org,
Avi Kivity <avi@...hat.com>
Cc: Ingo Molnar <mingo@...e.hu>,
Fr??d??ric Weisbecker <fweisbec@...il.com>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Cyrill Gorcunov <gorcunov@...il.com>,
Lin Ming <ming.m.lin@...el.com>,
Sheng Yang <sheng@...ux.intel.com>,
Marcelo Tosatti <mtosatti@...hat.com>,
oerg Roedel <joro@...tes.org>,
Jes Sorensen <Jes.Sorensen@...hat.com>,
Gleb Natapov <gleb@...hat.com>,
Zachary Amsden <zamsden@...hat.com>, zhiteng.huang@...el.com,
tim.c.chen@...el.com
Subject: [PATCH V2 2/5] ara virt interface of perf to support kvm guest os
statistics collection in guest os
The 2nd patch is to change the definition of perf_event to facilitate
perf attr copy when a hypercall happens.
Signed-off-by: Zhang Yanmin <yanmin_zhang@...ux.intel.com>
---
--- linux-2.6_tip0620/include/linux/perf_event.h 2010-06-21 15:19:52.821999849 +0800
+++ linux-2.6_tip0620perfkvm/include/linux/perf_event.h 2010-06-21 16:53:49.283999849 +0800
@@ -188,7 +188,10 @@ struct perf_event_attr {
__u64 sample_type;
__u64 read_format;
- __u64 disabled : 1, /* off by default */
+ union {
+ __u64 flags;
+ struct {
+ __u64 disabled : 1, /* off by default */
inherit : 1, /* children inherit it */
pinned : 1, /* must always be on PMU */
exclusive : 1, /* only group on PMU */
@@ -217,6 +220,8 @@ struct perf_event_attr {
mmap_data : 1, /* non-exec mmap data */
__reserved_1 : 46;
+ };
+ };
union {
__u32 wakeup_events; /* wakeup every n events */
@@ -465,12 +470,6 @@ enum perf_callchain_context {
# include <asm/local64.h>
#endif
-struct perf_guest_info_callbacks {
- int (*is_in_guest) (void);
- int (*is_user_mode) (void);
- unsigned long (*get_guest_ip) (void);
-};
-
#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <asm/hw_breakpoint.h>
#endif
@@ -753,6 +752,20 @@ struct perf_event {
perf_overflow_handler_t overflow_handler;
+ /*
+ * pointers used by kvm perf paravirt interface.
+ *
+ * 1) Used in host kernel and points to host_perf_shadow which
+ * has information about guest perf_event
+ */
+ void *host_perf_shadow;
+ /*
+ * 2) Used in guest kernel and points to guest_perf_shadow which
+ * is used as a communication area with host kernel. Host kernel
+ * copies overflow data to it when an event overflows.
+ */
+ void *guest_perf_shadow;
+
#ifdef CONFIG_EVENT_TRACING
struct ftrace_event_call *tp_event;
struct event_filter *filter;
@@ -838,6 +851,16 @@ struct perf_output_handle {
int sample;
};
+struct perf_guest_info_callbacks {
+ /* Support collect guest statistics from host side */
+ int (*is_in_guest) (void);
+ int (*is_user_mode) (void);
+ unsigned long (*get_guest_ip) (void);
+
+ /* Support paravirt interface */
+ void (*copy_event_to_shadow) (struct perf_event *event, int overflows);
+};
+
#ifdef CONFIG_PERF_EVENTS
/*
@@ -871,6 +894,10 @@ perf_event_create_kernel_counter(struct
perf_overflow_handler_t callback);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);
+extern void perf_event_output(struct perf_event *event, int nmi,
+ struct perf_sample_data *data, struct pt_regs *regs);
+void perf_event_attach(struct perf_event *event);
+void perf_event_detach(struct perf_event *event);
struct perf_sample_data {
u64 type;
@@ -1023,6 +1050,14 @@ perf_event_task_sched_in(struct task_str
static inline void
perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next) { }
+
+static inline void
+perf_event_output(struct perf_event *event, int nmi,
+ struct perf_sample_data *data, struct pt_regs *regs) { }
+
+static inline void perf_event_attach(struct perf_event *event) { }
+static inline void perf_event_detach(struct perf_event *event) { }
+
static inline void
perf_event_task_tick(struct task_struct *task) { }
static inline int perf_event_init_task(struct task_struct *child) { return 0; }
--- linux-2.6_tip0620/kernel/watchdog.c 2010-06-21 15:20:48.517999849 +0800
+++ linux-2.6_tip0620perfkvm/kernel/watchdog.c 2010-06-21 15:21:39.315999849 +0800
@@ -197,8 +197,6 @@ static struct perf_event_attr wd_hw_attr
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
.size = sizeof(struct perf_event_attr),
- .pinned = 1,
- .disabled = 1,
};
/* Callback function for perf event subsystem */
@@ -361,6 +359,8 @@ static int watchdog_nmi_enable(int cpu)
/* Try to register using hardware perf events */
wd_attr = &wd_hw_attr;
wd_attr->sample_period = hw_nmi_get_sample_period();
+ wd_attr->pinned = 1;
+ wd_attr->disabled = 1;
event = perf_event_create_kernel_counter(wd_attr, cpu, -1, watchdog_overflow_callback);
if (!IS_ERR(event)) {
printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
--- linux-2.6_tip0620/kernel/perf_event.c 2010-06-21 15:20:49.013999849 +0800
+++ linux-2.6_tip0620perfkvm/kernel/perf_event.c 2010-06-21 16:52:35.432999849 +0800
@@ -32,6 +32,7 @@
#include <linux/perf_event.h>
#include <linux/ftrace_event.h>
#include <linux/hw_breakpoint.h>
+#include <linux/kvm_para.h>
#include <asm/irq_regs.h>
@@ -747,6 +748,7 @@ static int group_can_go_on(struct perf_e
*/
if (event->attr.exclusive && cpuctx->active_oncpu)
return 0;
+
/*
* Otherwise, try to add it if all previous groups were able
* to go on.
@@ -1613,6 +1615,7 @@ void perf_event_task_tick(struct task_st
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
int rotate = 0;
+ int adjust_freq = 1;
if (!atomic_read(&nr_events))
return;
@@ -1626,9 +1629,22 @@ void perf_event_task_tick(struct task_st
if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active)
rotate = 1;
- perf_ctx_adjust_freq(&cpuctx->ctx);
- if (ctx)
- perf_ctx_adjust_freq(ctx);
+#ifdef CONFIG_KVM_PERF
+ if (kvm_para_available()) {
+ /*
+ * perf_ctx_adjust_freq causes lots of pmu->read which would
+ * trigger too many vmexit to host kernel. We disable it
+ * under para virt situation
+ */
+ adjust_freq = 0;
+ }
+#endif
+
+ if (adjust_freq) {
+ perf_ctx_adjust_freq(&cpuctx->ctx);
+ if (ctx)
+ perf_ctx_adjust_freq(ctx);
+ }
if (!rotate)
return;
@@ -3434,7 +3450,7 @@ void perf_prepare_sample(struct perf_eve
}
}
-static void perf_event_output(struct perf_event *event, int nmi,
+void perf_event_output(struct perf_event *event, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
@@ -5261,6 +5277,47 @@ perf_event_create_kernel_counter(struct
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+void perf_event_attach(struct perf_event *event)
+{
+ struct perf_event_context *old_ctx, *new_ctx;
+
+ old_ctx = event->ctx;
+ new_ctx = find_get_context(current->pid, -1);
+ if (old_ctx != new_ctx) {
+ if (old_ctx) {
+ /* Delete from old ctx before joining new ctx */
+ mutex_lock(&old_ctx->mutex);
+ raw_spin_lock(&old_ctx->lock);
+ list_del_event(event, old_ctx);
+ raw_spin_unlock(&old_ctx->lock);
+ mutex_unlock(&old_ctx->mutex);
+ put_ctx(old_ctx);
+ }
+
+ mutex_lock(&new_ctx->mutex);
+ raw_spin_lock(&new_ctx->lock);
+ list_add_event(event, new_ctx);
+ event->ctx = new_ctx;
+ raw_spin_unlock(&new_ctx->lock);
+ mutex_unlock(&new_ctx->mutex);
+ } else
+ put_ctx(new_ctx);
+
+ perf_event_enable(event);
+}
+EXPORT_SYMBOL_GPL(perf_event_attach);
+
+void perf_event_detach(struct perf_event *event)
+{
+ /*
+ * Just disable the event and don't del it from
+ * ctx->event_list in case there is a race condition
+ * with perf_event_read_value
+ */
+ perf_event_disable(event);
+}
+EXPORT_SYMBOL_GPL(perf_event_detach);
+
/*
* inherit a event from parent task to child task:
*/
--
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