perf kvm: Add live mode for analyzing events

index a41dc4a..a409b25 100644
@@ -189,6 +189,60 @@ int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 	return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
 }
 
+static int trace_event__id(const char *evname)
+{
+	char *filename, *colon;
+	int err = -1, fd;
+
+	if (asprintf(&filename, "%s/%s/id", tracing_events_path, evname) < 0)
+		return -1;
+
+	colon = strrchr(filename, ':');
+	if (colon != NULL)
+		*colon = '/';
+
+	fd = open(filename, O_RDONLY);
+	if (fd >= 0) {
+		char id[16];
+		if (read(fd, id, sizeof(id)) > 0)
+			err = atoi(id);
+		close(fd);
+	}
+
+	free(filename);
+	return err;
+}
+
+int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
+				 const char * const tracepoints[],
+				 size_t nr_tracepoints)
+{
+	int err;
+	size_t i;
+	struct perf_event_attr *attrs = zalloc(nr_tracepoints * sizeof(*attrs));
+
+	if (attrs == NULL)
+		return -1;
+
+	for (i = 0; i < nr_tracepoints; i++) {
+		err = trace_event__id(tracepoints[i]);
+
+		if (err < 0)
+			goto out_free_attrs;
+
+		attrs[i].type	       = PERF_TYPE_TRACEPOINT;
+		attrs[i].config	       = err;
+		attrs[i].sample_type   = (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
+					  PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD);
+		attrs[i].sample_period = 1;
+	}
+
+	err = perf_evlist__add_attrs(evlist, attrs, nr_tracepoints);
+out_free_attrs:
+	free(attrs);
+	return err;
+}
+
 struct perf_evsel *
 perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
 {

index 56003f7..be85147 100644
@@ -53,6 +53,9 @@ void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
 int perf_evlist__add_default(struct perf_evlist *evlist);
 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 				     struct perf_event_attr *attrs, size_t nr_attrs);
+int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
+				 const char * const tracepoints[],
+				 size_t nr_tracepoints);
 
 #define perf_evlist__add_default_attrs(evlist, array) \
 	__perf_evlist__add_default_attrs(evlist, array, ARRAY_SIZE(array))

index a409b25..7fff06f 100644
@@ -189,6 +189,45 @@ int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 	return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
 }
 
+static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
+						struct pevent *pevent)
+{
+	struct event_format *event;
+	char bf[128];
+
+	/* already prepared */
+	if (evsel->tp_format)
+		return 0;
+
+	event = pevent_find_event(pevent, evsel->attr.config);
+	if (event == NULL)
+		return -1;
+
+	if (!evsel->name) {
+		snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);
+		evsel->name = strdup(bf);
+		if (evsel->name == NULL)
+			return -1;
+	}
+
+	evsel->tp_format = event;
+	return 0;
+}
+
+int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
+						  struct pevent *pevent)
+{
+	struct perf_evsel *pos;
+
+	list_for_each_entry(pos, &evlist->entries, node) {
+		if (pos->attr.type == PERF_TYPE_TRACEPOINT &&
+		    perf_evsel__prepare_tracepoint_event(pos, pevent))
+			return -1;
+	}
+
+	return 0;
+}
+
 static int trace_event__id(const char *evname)
 {
 	char *filename, *colon;

index be85147..9959954 100644
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include "../perf.h"
 #include "event.h"
+#include "event-parse.h"
 #include "evsel.h"
 #include "util.h"
 #include <unistd.h>

@@ -53,6 +54,9 @@ void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
 int perf_evlist__add_default(struct perf_evlist *evlist);
 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 				     struct perf_event_attr *attrs, size_t nr_attrs);
+int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
+					   struct pevent *pevent);
+
 int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
 				 const char * const tracepoints[],
 				 size_t nr_tracepoints);

index 7daad23..42f8ec9 100644
@@ -2553,45 +2553,6 @@ static int read_attr(int fd, struct perf_header *ph,
 	return ret <= 0 ? -1 : 0;
 }
 
-static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
-						struct pevent *pevent)
-{
-	struct event_format *event;
-	char bf[128];
-
-	/* already prepared */
-	if (evsel->tp_format)
-		return 0;
-
-	event = pevent_find_event(pevent, evsel->attr.config);
-	if (event == NULL)
-		return -1;
-
-	if (!evsel->name) {
-		snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);
-		evsel->name = strdup(bf);
-		if (evsel->name == NULL)
-			return -1;
-	}
-
-	evsel->tp_format = event;
-	return 0;
-}
-
-static int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
-						  struct pevent *pevent)
-{
-	struct perf_evsel *pos;
-
-	list_for_each_entry(pos, &evlist->entries, node) {
-		if (pos->attr.type == PERF_TYPE_TRACEPOINT &&
-		    perf_evsel__prepare_tracepoint_event(pos, pevent))
-			return -1;
-	}
-
-	return 0;
-}
-
 int perf_session__read_header(struct perf_session *session, int fd)
 {
 	struct perf_header *header = &session->header;

index 15abe40..23d2ea3 100644
@@ -14,7 +14,6 @@
 #include "sort.h"
 #include "util.h"
 #include "cpumap.h"
-#include "event-parse.h"
 #include "perf_regs.h"
 #include "unwind.h"
 #include "vdso.h"

index 7fff06f..d77135b 100644
@@ -14,6 +14,7 @@
 #include "target.h"
 #include "evlist.h"
 #include "evsel.h"
+#include "trace-event.h"
 #include <unistd.h>
 
 #include "parse-events.h"

@@ -228,6 +229,32 @@ int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
 	return 0;
 }
 
+int perf_evlist__trace_init(struct perf_evlist *evlist,
+			    struct perf_session *session)
+{
+	struct tracing_data *tdata;
+	char temp_file[] = "/tmp/perf-XXXXXXXX";
+	int fd;
+
+	fd = mkstemp(temp_file);
+	if (fd < 0) {
+		pr_err("mkstemp failed\n");
+		return -1;
+	}
+	unlink(temp_file);
+
+	tdata = tracing_data_get(&evlist->entries, fd, false);
+	if (!tdata)
+		return -1;
+
+	lseek(fd, 0, SEEK_SET);
+	(void) trace_report(fd, &session->pevent, false);
+	tracing_data_put(tdata);
+
+	return perf_evlist__prepare_tracepoint_events(evlist, session->pevent);
+}
+
+
 static int trace_event__id(const char *evname)
 {
 	char *filename, *colon;

index 9959954..e375a18 100644
@@ -8,6 +8,7 @@
 #include "event-parse.h"
 #include "evsel.h"
 #include "util.h"
+#include "session.h"
 #include <unistd.h>
 
 struct pollfd;

@@ -60,6 +61,8 @@ int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
 int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
 				 const char * const tracepoints[],
 				 size_t nr_tracepoints);
+int perf_evlist__trace_init(struct perf_evlist *evlist,
+			    struct perf_session *session);
 
 #define perf_evlist__add_default_attrs(evlist, array) \
 	__perf_evlist__add_default_attrs(evlist, array, ARRAY_SIZE(array))

index 23d2ea3..576ab8b 100644
@@ -456,7 +456,7 @@ static int process_finished_round(struct perf_tool *tool,
 				  union perf_event *event,
 				  struct perf_session *session);
 
-static void perf_tool__fill_defaults(struct perf_tool *tool)
+void perf_tool__fill_defaults(struct perf_tool *tool)
 {
 	if (tool->sample == NULL)
 		tool->sample = process_event_sample_stub;

@@ -702,8 +702,8 @@ static int perf_session_deliver_event(struct perf_session *session,
 				      struct perf_tool *tool,
 				      u64 file_offset);
 
-static int flush_sample_queue(struct perf_session *s,
-			       struct perf_tool *tool)
+int flush_sample_queue(struct perf_session *s,
+		       struct perf_tool *tool)
 {
 	struct ordered_samples *os = &s->ordered_samples;
 	struct list_head *head = &os->samples;

@@ -1150,10 +1150,10 @@ static void event_swap(union perf_event *event, bool sample_id_all)
 		swap(event, sample_id_all);
 }
 
-static int perf_session__process_event(struct perf_session *session,
-				       union perf_event *event,
-				       struct perf_tool *tool,
-				       u64 file_offset)
+int perf_session__process_event(struct perf_session *session,
+				union perf_event *event,
+				struct perf_tool *tool,
+				u64 file_offset)
 {
 	struct perf_sample sample;
 	int ret;

index aab414f..3fb5049 100644
@@ -63,6 +63,15 @@ int __perf_session__process_events(struct perf_session *self,
 int perf_session__process_events(struct perf_session *self,
 				 struct perf_tool *tool);
 
+int perf_session__process_event(struct perf_session *session,
+				union perf_event *event,
+				struct perf_tool *tool,
+				u64 file_offset);
+
+int flush_sample_queue(struct perf_session *s, struct perf_tool *tool);
+
+void perf_tool__fill_defaults(struct perf_tool *tool);
+
 int perf_session__resolve_callchain(struct perf_session *self, struct perf_evsel *evsel,
 				    struct thread *thread,
 				    struct ip_callchain *chain,

index fb9da71..a053812 100644
@@ -263,8 +263,6 @@ out_unlock:
 	pthread_mutex_unlock(&notes->lock);
 }
 
-static const char		CONSOLE_CLEAR[] = "";
-
 static struct hist_entry *perf_evsel__add_hist_entry(struct perf_evsel *evsel,
 						     struct addr_location *al,
 						     struct perf_sample *sample)

index 86ff1b1..8630570 100644
@@ -47,6 +47,8 @@ struct perf_top {
 	const char	   *sym_filter;
 };
 
+#define CONSOLE_CLEAR ""
+
 size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size);
 void perf_top__reset_sample_counters(struct perf_top *top);
 #endif /* __PERF_TOP_H */

index 260abc5..a23db89 100644
@@ -313,9 +313,9 @@ struct vcpu_event_record {
 
 static void init_kvm_event_record(struct perf_kvm *kvm)
 {
-	int i;
+	unsigned int i;
 
-	for (i = 0; i < (int)EVENTS_CACHE_SIZE; i++)
+	for (i = 0; i < EVENTS_CACHE_SIZE; i++)
 		INIT_LIST_HEAD(&kvm->kvm_events_cache[i]);
 }
 

index b98095e..8416754 100644
@@ -313,9 +313,9 @@ struct vcpu_event_record {
 
 static void init_kvm_event_record(struct perf_kvm *kvm)
 {
-	int i;
+	unsigned int i;
 
-	for (i = 0; i < (int)EVENTS_CACHE_SIZE; i++)
+	for (i = 0; i < EVENTS_CACHE_SIZE; i++)
 		INIT_LIST_HEAD(&kvm->kvm_events_cache[i]);
 }
 

index a23db89..af74a97 100644
@@ -327,6 +327,7 @@ static int kvm_events_hash_fn(u64 key)
 static bool kvm_event_expand(struct kvm_event *event, int vcpu_id)
 {
 	int old_max_vcpu = event->max_vcpu;
+	void *prev;
 
 	if (vcpu_id < event->max_vcpu)
 		return true;

@@ -334,9 +335,11 @@ static bool kvm_event_expand(struct kvm_event *event, int vcpu_id)
 	while (event->max_vcpu <= vcpu_id)
 		event->max_vcpu += DEFAULT_VCPU_NUM;
 
+	prev = event->vcpu;
 	event->vcpu = realloc(event->vcpu,
 			      event->max_vcpu * sizeof(*event->vcpu));
 	if (!event->vcpu) {
+		free(prev);
 		pr_err("Not enough memory\n");
 		return false;
 	}

index af74a97..43fd71c 100644
@@ -372,9 +372,10 @@ static struct kvm_event *find_create_kvm_event(struct perf_kvm *kvm,
 	BUG_ON(key->key == INVALID_KEY);
 
 	head = &kvm->kvm_events_cache[kvm_events_hash_fn(key->key)];
-	list_for_each_entry(event, head, hash_entry)
+	list_for_each_entry(event, head, hash_entry) {
 		if (event->key.key == key->key && event->key.info == key->info)
 			return event;
+	}
 
 	event = kvm_alloc_init_event(key);
 	if (!event)

@@ -599,13 +600,15 @@ static void sort_result(struct perf_kvm *kvm)
 	int vcpu = kvm->trace_vcpu;
 	struct kvm_event *event;
 
-	for (i = 0; i < EVENTS_CACHE_SIZE; i++)
-		list_for_each_entry(event, &kvm->kvm_events_cache[i], hash_entry)
+	for (i = 0; i < EVENTS_CACHE_SIZE; i++) {
+		list_for_each_entry(event, &kvm->kvm_events_cache[i], hash_entry) {
 			if (event_is_valid(event, vcpu)) {
 				update_total_count(kvm, event);
 				insert_to_result(&kvm->result, event,
 						 kvm->compare, vcpu);
 			}
+		}
+	}
 }
 
 /* returns left most element of result, and erase it */

index 72a302e..836c82f 100644
@@ -369,9 +369,10 @@ static struct kvm_event *find_create_kvm_event(struct perf_kvm *kvm,
 	BUG_ON(key->key == INVALID_KEY);
 
 	head = &kvm->kvm_events_cache[kvm_events_hash_fn(key->key)];
-	list_for_each_entry(event, head, hash_entry)
+	list_for_each_entry(event, head, hash_entry) {
 		if (event->key.key == key->key && event->key.info == key->info)
 			return event;
+	}
 
 	event = kvm_alloc_init_event(key);
 	if (!event)

@@ -610,13 +611,15 @@ static void sort_result(struct perf_kvm *kvm)
 	int vcpu = kvm->trace_vcpu;
 	struct kvm_event *event;
 
-	for (i = 0; i < EVENTS_CACHE_SIZE; i++)
-		list_for_each_entry(event, &kvm->kvm_events_cache[i], hash_entry)
+	for (i = 0; i < EVENTS_CACHE_SIZE; i++) {
+		list_for_each_entry(event, &kvm->kvm_events_cache[i], hash_entry) {
 			if (event_is_valid(event, vcpu)) {
 				update_total_count(kvm, event);
 				insert_to_result(&kvm->result, event,
 						 kvm->compare, vcpu);
 			}
+		}
+	}
 }
 
 /* returns left most element of result, and erase it */

index 43fd71c..f6091d2 100644
@@ -784,16 +784,11 @@ exit:
 	return ret;
 }
 
-static const char * const record_args[] = {
-	"record",
-	"-R",
-	"-f",
-	"-m", "1024",
-	"-c", "1",
-	"-e", "kvm:kvm_entry",
-	"-e", "kvm:kvm_exit",
-	"-e", "kvm:kvm_mmio",
-	"-e", "kvm:kvm_pio",
+static const char * const kvm_events_tp[] = {
+	"kvm:kvm_entry",
+	"kvm:kvm_exit",
+	"kvm:kvm_mmio",
+	"kvm:kvm_pio",
 };
 
 #define STRDUP_FAIL_EXIT(s)		\

@@ -808,8 +803,16 @@ static int kvm_events_record(struct perf_kvm *kvm, int argc, const char **argv)
 {
 	unsigned int rec_argc, i, j;
 	const char **rec_argv;
+	const char * const record_args[] = {
+		"record",
+		"-R",
+		"-f",
+		"-m", "1024",
+		"-c", "1",
+	};
 
-	rec_argc = ARRAY_SIZE(record_args) + argc + 2;
+	rec_argc = ARRAY_SIZE(record_args) + argc + 2 +
+		   ARRAY_SIZE(kvm_events_tp);
 	rec_argv = calloc(rec_argc + 1, sizeof(char *));
 
 	if (rec_argv == NULL)

@@ -818,6 +821,11 @@ static int kvm_events_record(struct perf_kvm *kvm, int argc, const char **argv)
 	for (i = 0; i < ARRAY_SIZE(record_args); i++)
 		rec_argv[i] = STRDUP_FAIL_EXIT(record_args[i]);
 
+	for (j = 0; j < ARRAY_SIZE(kvm_events_tp); j++) {
+		rec_argv[i++] = "-e";
+		rec_argv[i++] = STRDUP_FAIL_EXIT(kvm_events_tp[j]);
+	}
+
 	rec_argv[i++] = STRDUP_FAIL_EXIT("-o");
 	rec_argv[i++] = STRDUP_FAIL_EXIT(kvm->file_name);
 

index f6091d2..6412694 100644
@@ -665,8 +665,8 @@ static void print_result(struct perf_kvm *kvm)
 		pr_info("\n");
 	}
 
-	pr_info("\nTotal Samples:%lld, Total events handled time:%.2fus.\n\n",
-		(unsigned long long)kvm->total_count, kvm->total_time / 1e3);
+	pr_info("\nTotal Samples:%" PRIu64 ", Total events handled time:%.2fus.\n\n",
+		kvm->total_count, kvm->total_time / 1e3);
 }
 
 static int process_sample_event(struct perf_tool *tool,

index 8416754..72a302e 100644
@@ -673,8 +673,8 @@ static void print_result(struct perf_kvm *kvm)
 		pr_info("\n");
 	}
 
-	pr_info("\nTotal Samples:%lld, Total events handled time:%.2fus.\n\n",
-		(unsigned long long)kvm->total_count, kvm->total_time / 1e3);
+	pr_info("\nTotal Samples:%" PRIu64 ", Total events handled time:%.2fus.\n\n",
+		kvm->total_count, kvm->total_time / 1e3);
 }
 
 static int process_sample_event(struct perf_tool *tool,

index 6412694..dcbbcc7 100644
@@ -420,7 +420,10 @@ static double kvm_event_rel_stddev(int vcpu_id, struct kvm_event *event)
 static bool update_kvm_event(struct kvm_event *event, int vcpu_id,
 			     u64 time_diff)
 {
-	kvm_update_event_stats(&event->total, time_diff);
+	if (vcpu_id == -1) {
+		kvm_update_event_stats(&event->total, time_diff);
+		return true;
+	}
 
 	if (!kvm_event_expand(event, vcpu_id))
 		return false;

@@ -436,6 +439,12 @@ static bool handle_end_event(struct perf_kvm *kvm,
 {
 	struct kvm_event *event;
 	u64 time_begin, time_diff;
+	int vcpu;
+
+	if (kvm->trace_vcpu == -1)
+		vcpu = -1;
+	else
+		vcpu = vcpu_record->vcpu_id;
 
 	event = vcpu_record->last_event;
 	time_begin = vcpu_record->start_time;

@@ -465,7 +474,7 @@ static bool handle_end_event(struct perf_kvm *kvm,
 	BUG_ON(timestamp < time_begin);
 
 	time_diff = timestamp - time_begin;
-	return update_kvm_event(event, vcpu_record->vcpu_id, time_diff);
+	return update_kvm_event(event, vcpu, time_diff);
 }
 
 static

@@ -502,6 +511,11 @@ static bool handle_kvm_event(struct perf_kvm *kvm,
 	if (!vcpu_record)
 		return true;
 
+	/* only process events for vcpus user cares about */
+	if ((kvm->trace_vcpu != -1) &&
+	    (kvm->trace_vcpu != vcpu_record->vcpu_id))
+		return true;
+
 	if (kvm->events_ops->is_begin_event(evsel, sample, &key))
 		return handle_begin_event(kvm, vcpu_record, &key, sample->time);
 

index 260abc5..b98095e 100644
@@ -416,7 +416,10 @@ static double kvm_event_rel_stddev(int vcpu_id, struct kvm_event *event)
 static bool update_kvm_event(struct kvm_event *event, int vcpu_id,
 			     u64 time_diff)
 {
-	kvm_update_event_stats(&event->total, time_diff);
+	if (vcpu_id == -1) {
+		kvm_update_event_stats(&event->total, time_diff);
+		return true;
+	}
 
 	if (!kvm_event_expand(event, vcpu_id))
 		return false;

@@ -432,6 +435,12 @@ static bool handle_end_event(struct perf_kvm *kvm,
 {
 	struct kvm_event *event;
 	u64 time_begin, time_diff;
+	int vcpu;
+
+	if (kvm->trace_vcpu == -1)
+		vcpu = -1;
+	else
+		vcpu = vcpu_record->vcpu_id;
 
 	event = vcpu_record->last_event;
 	time_begin = vcpu_record->start_time;

@@ -461,7 +470,7 @@ static bool handle_end_event(struct perf_kvm *kvm,
 	BUG_ON(timestamp < time_begin);
 
 	time_diff = timestamp - time_begin;
-	return update_kvm_event(event, vcpu_record->vcpu_id, time_diff);
+	return update_kvm_event(event, vcpu, time_diff);
 }
 
 static

@@ -498,6 +507,11 @@ static bool handle_kvm_event(struct perf_kvm *kvm,
 	if (!vcpu_record)
 		return true;
 
+	/* only process events for vcpus user cares about */
+	if ((kvm->trace_vcpu != -1) &&
+	    (kvm->trace_vcpu != vcpu_record->vcpu_id))
+		return true;
+
 	if (kvm->events_ops->is_begin_event(evsel, sample, &key))
 		return handle_begin_event(kvm, vcpu_record, &key, sample->time);
 

index dcbbcc7..9dd1921 100644
@@ -2,6 +2,7 @@
 #include "perf.h"
 
 #include "util/evsel.h"
+#include "util/evlist.h"
 #include "util/util.h"
 #include "util/cache.h"
 #include "util/symbol.h"

@@ -15,9 +16,12 @@
 #include "util/debugfs.h"
 #include "util/tool.h"
 #include "util/stat.h"
+#include "util/top.h"
 
 #include <sys/prctl.h>
+#include <sys/timerfd.h>
 
+#include <termios.h>
 #include <semaphore.h>
 #include <pthread.h>
 #include <math.h>

@@ -81,6 +85,8 @@ struct exit_reasons_table {
 
 struct perf_kvm {
 	struct perf_tool    tool;
+	struct perf_record_opts opts;
+	struct perf_evlist  *evlist;
 	struct perf_session *session;
 
 	const char *file_name;

@@ -95,10 +101,16 @@ struct perf_kvm {
 	struct kvm_events_ops *events_ops;
 	key_cmp_fun compare;
 	struct list_head kvm_events_cache[EVENTS_CACHE_SIZE];
+
 	u64 total_time;
 	u64 total_count;
+	u64 lost_events;
 
 	struct rb_root result;
+
+	int timerfd;
+	unsigned int display_time;
+	bool live;
 };
 
 

@@ -319,6 +331,23 @@ static void init_kvm_event_record(struct perf_kvm *kvm)
 		INIT_LIST_HEAD(&kvm->kvm_events_cache[i]);
 }
 
+static void clear_events_cache_stats(struct list_head *kvm_events_cache)
+{
+	struct list_head *head;
+	struct kvm_event *event;
+	unsigned int i;
+
+	for (i = 0; i < EVENTS_CACHE_SIZE; i++) {
+		head = &kvm_events_cache[i];
+		list_for_each_entry(event, head, hash_entry) {
+			/* reset stats for event */
+			memset(&event->total, 0, sizeof(event->total));
+			memset(event->vcpu, 0,
+			       event->max_vcpu * sizeof(*event->vcpu));
+		}
+	}
+}
+
 static int kvm_events_hash_fn(u64 key)
 {
 	return key & (EVENTS_CACHE_SIZE - 1);

@@ -471,7 +500,11 @@ static bool handle_end_event(struct perf_kvm *kvm,
 	vcpu_record->last_event = NULL;
 	vcpu_record->start_time = 0;
 
-	BUG_ON(timestamp < time_begin);
+	/* seems to happen once in a while during live mode */
+	if (timestamp < time_begin) {
+		pr_debug("End time before begin time; skipping event.\n");
+		return true;
+	}
 
 	time_diff = timestamp - time_begin;
 	return update_kvm_event(event, vcpu, time_diff);

@@ -637,24 +670,60 @@ static struct kvm_event *pop_from_result(struct rb_root *result)
 	return container_of(node, struct kvm_event, rb);
 }
 
-static void print_vcpu_info(int vcpu)
+static void print_vcpu_info(struct perf_kvm *kvm)
 {
+	int vcpu = kvm->trace_vcpu;
+
 	pr_info("Analyze events for ");
 
+	if (kvm->live) {
+		if (kvm->opts.target.system_wide)
+			pr_info("all VMs, ");
+		else if (kvm->opts.target.pid)
+			pr_info("pid(s) %s, ", kvm->opts.target.pid);
+		else if (kvm->opts.target.tid)
+			pr_info("tid(s) %s, ", kvm->opts.target.tid);
+		else if (kvm->opts.target.cpu_list)
+			pr_info("host cpu(s) %s, ", kvm->opts.target.cpu_list);
+		else
+			pr_info("dazed and confused on what is monitored, ");
+	}
+
 	if (vcpu == -1)
 		pr_info("all VCPUs:\n\n");
 	else
 		pr_info("VCPU %d:\n\n", vcpu);
 }
 
+static void show_timeofday(void)
+{
+	char date[64];
+	struct timeval tv;
+	struct tm ltime;
+
+	gettimeofday(&tv, NULL);
+	if (localtime_r(&tv.tv_sec, &ltime)) {
+		strftime(date, sizeof(date), "%H:%M:%S", &ltime);
+		pr_info("%s.%06ld", date, tv.tv_usec);
+	} else
+		pr_info("00:00:00.000000");
+
+	return;
+}
+
 static void print_result(struct perf_kvm *kvm)
 {
 	char decode[20];
 	struct kvm_event *event;
 	int vcpu = kvm->trace_vcpu;
 
+	if (kvm->live) {
+		puts(CONSOLE_CLEAR);
+		show_timeofday();
+	}
+
 	pr_info("\n\n");
-	print_vcpu_info(vcpu);
+	print_vcpu_info(kvm);
 	pr_info("%20s ", kvm->events_ops->name);
 	pr_info("%10s ", "Samples");
 	pr_info("%9s ", "Samples%");

@@ -681,6 +750,20 @@ static void print_result(struct perf_kvm *kvm)
 
 	pr_info("\nTotal Samples:%" PRIu64 ", Total events handled time:%.2fus.\n\n",
 		kvm->total_count, kvm->total_time / 1e3);
+
+	if (kvm->lost_events)
+		pr_info("\nLost events: %" PRIu64 "\n\n", kvm->lost_events);
+}
+
+static int process_lost_event(struct perf_tool *tool,
+			      union perf_event *event __maybe_unused,
+			      struct perf_sample *sample __maybe_unused,
+			      struct machine *machine __maybe_unused)
+{
+	struct perf_kvm *kvm = container_of(tool, struct perf_kvm, tool);
+
+	kvm->lost_events++;
+	return 0;
 }
 
 static int process_sample_event(struct perf_tool *tool,

@@ -704,10 +787,20 @@ static int process_sample_event(struct perf_tool *tool,
 	return 0;
 }
 
-static int get_cpu_isa(struct perf_session *session)
+static int cpu_isa_config(struct perf_kvm *kvm)
 {
-	char *cpuid = session->header.env.cpuid;
-	int isa;
+	char buf[64], *cpuid;
+	int err, isa;
+
+	if (kvm->live) {
+		err = get_cpuid(buf, sizeof(buf));
+		if (err != 0) {
+			pr_err("Failed to look up CPU type (Intel or AMD)\n");
+			return err;
+		}
+		cpuid = buf;
+	} else
+		cpuid = kvm->session->header.env.cpuid;
 
 	if (strstr(cpuid, "Intel"))
 		isa = 1;

@@ -715,10 +808,374 @@ static int get_cpu_isa(struct perf_session *session)
 		isa = 0;
 	else {
 		pr_err("CPU %s is not supported.\n", cpuid);
-		isa = -ENOTSUP;
+		return -ENOTSUP;
+	}
+
+	if (isa == 1) {
+		kvm->exit_reasons = vmx_exit_reasons;
+		kvm->exit_reasons_size = ARRAY_SIZE(vmx_exit_reasons);
+		kvm->exit_reasons_isa = "VMX";
+	}
+
+	return 0;
+}
+
+static bool verify_vcpu(int vcpu)
+{
+	if (vcpu != -1 && vcpu < 0) {
+		pr_err("Invalid vcpu:%d.\n", vcpu);
+		return false;
+	}
+
+	return true;
+}
+
+#define PERF_KVM__MAX_EVENTS_PER_MMAP  1000
+
+static s64 perf_kvm__mmap_read_idx(struct perf_kvm *kvm, int idx)
+{
+	union perf_event *event;
+	s64 n = 0;
+	int err;
+
+	while ((event = perf_evlist__mmap_read(kvm->evlist, idx)) != NULL) {
+		err = perf_session__process_event(kvm->session, event,
+						  &kvm->tool, 0);
+		if (err) {
+			pr_err("Failed to process event\n");
+			return err;
+		}
+		n++;
+
+		/* limit events per mmap handled all at once */
+		if (n == PERF_KVM__MAX_EVENTS_PER_MMAP)
+			break;
+	}
+
+	return n;
+}
+
+static int perf_kvm__mmap_read(struct perf_kvm *kvm)
+{
+	int i, err, throttled = 0;
+	s64 n, ntotal = 0;
+
+	for (i = 0; i < kvm->evlist->nr_mmaps; i++) {
+		n = perf_kvm__mmap_read_idx(kvm, i);
+		if (n < 0)
+			return -1;
+		ntotal += n;
+		if (n == PERF_KVM__MAX_EVENTS_PER_MMAP)
+			throttled = 1;
+	}
+
+	/* flush queue after each round in which we processed events */
+	if (ntotal) {
+		err = kvm->tool.finished_round(&kvm->tool, NULL, kvm->session);
+		if (err) {
+			if (kvm->lost_events)
+				pr_info("\nLost events: %" PRIu64 "\n\n",
+					kvm->lost_events);
+			return err;
+		}
+	}
+
+	return throttled;
+}
+
+static volatile int done;
+
+static void sig_handler(int sig)
+{
+	if (sig == SIGINT)
+		done = 1;
+}
+
+static int perf_kvm__timerfd_create(struct perf_kvm *kvm)
+{
+	struct itimerspec new_value;
+	struct timespec now;
+	int rc = -1;
+
+	kvm->timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+	if (kvm->timerfd < 0) {
+		pr_err("timerfd_create failed\n");
+		goto out;
+	}
+
+	if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) {
+		pr_err("clock_gettime failed: %d\n", errno);
+		close(kvm->timerfd);
+		goto out;
+	}
+
+	new_value.it_value.tv_sec = now.tv_sec + kvm->display_time;
+	new_value.it_value.tv_nsec = now.tv_nsec;
+	new_value.it_interval.tv_sec = kvm->display_time;
+	new_value.it_interval.tv_nsec = 0;
+
+	if (timerfd_settime(kvm->timerfd, TFD_TIMER_ABSTIME,
+			    &new_value, NULL) != 0) {
+		pr_err("timerfd_settime failed: %d\n", errno);
+		close(kvm->timerfd);
+		goto out;
+	}
+
+	rc = 0;
+out:
+	return rc;
+}
+
+static int perf_kvm__handle_timerfd(struct perf_kvm *kvm)
+{
+	uint64_t c;
+	int rc;
+
+	rc = read(kvm->timerfd, &c, sizeof(uint64_t));
+	if (rc < 0) {
+		if (errno == EAGAIN)
+			return 0;
+
+		pr_err("Failed to read timer fd: %d\n", errno);
+		return -1;
+	}
+
+	if (rc != sizeof(uint64_t)) {
+		pr_err("Error reading timer fd - invalid size returned\n");
+		return -1;
+	}
+
+	if (c != 1)
+		pr_debug("Missed timer beats: %" PRIu64 "\n", c-1);
+
+	/* update display */
+	sort_result(kvm);
+	print_result(kvm);
+
+	/* reset counts */
+	clear_events_cache_stats(kvm->kvm_events_cache);
+	kvm->total_count = 0;
+	kvm->total_time = 0;
+	kvm->lost_events = 0;
+
+	return 0;
+}
+
+static int fd_set_nonblock(int fd)
+{
+	long arg = 0;
+
+	arg = fcntl(fd, F_GETFL);
+	if (arg < 0) {
+		pr_err("Failed to get current flags for fd %d\n", fd);
+		return -1;
+	}
+
+	if (fcntl(fd, F_SETFL, arg | O_NONBLOCK) < 0) {
+		pr_err("Failed to set non-block option on fd %d\n", fd);
+		return -1;
 	}
 
-	return isa;
+	return 0;
+}
+
+static
+int perf_kvm__handle_stdin(struct termios *tc_now, struct termios *tc_save)
+{
+	int c;
+
+	tcsetattr(0, TCSANOW, tc_now);
+	c = getc(stdin);
+	tcsetattr(0, TCSAFLUSH, tc_save);
+
+	if (c == 'q')
+		return 1;
+
+	/* TO-DO: add hook for 'd' to change display rate
+	 *        needs an update to timerfd too
+	 */
+
+	return 0;
+}
+
+static int kvm_events_live_report(struct perf_kvm *kvm)
+{
+	struct pollfd *pollfds = NULL;
+	int nr_fds, ret, err = -EINVAL;
+	struct termios tc, save;
+
+	/* live flag must be set first */
+	kvm->live = true;
+
+	ret = cpu_isa_config(kvm);
+	if (ret < 0)
+		return ret;
+
+	if (!verify_vcpu(kvm->trace_vcpu) ||
+	    !select_key(kvm) ||
+	    !register_kvm_events_ops(kvm)) {
+		goto out;
+	}
+
+	init_kvm_event_record(kvm);
+
+
+	tcgetattr(0, &save);
+	tc = save;
+	tc.c_lflag &= ~(ICANON | ECHO);
+	tc.c_cc[VMIN] = 0;
+	tc.c_cc[VTIME] = 0;
+
+	signal(SIGINT, sig_handler);
+
+
+	/* copy pollfds -- need to add timerfd and stdin */
+	nr_fds = kvm->evlist->nr_fds;
+	pollfds = zalloc(sizeof(struct pollfd) * (nr_fds + 2));
+	if (!pollfds) {
+		err = -ENOMEM;
+		goto out;
+	}
+	memcpy(pollfds, kvm->evlist->pollfd,
+		sizeof(struct pollfd) * kvm->evlist->nr_fds);
+
+	/* add timer fd */
+	if (perf_kvm__timerfd_create(kvm) < 0) {
+		err = -1;
+		goto out;
+	}
+
+	pollfds[nr_fds].fd = kvm->timerfd;
+	pollfds[nr_fds].events = POLLIN;
+	nr_fds++;
+
+	pollfds[nr_fds].fd = fileno(stdin);
+	pollfds[nr_fds].events = POLLIN;
+	nr_fds++;
+	if (fd_set_nonblock(fileno(stdin)) != 0)
+		goto out;
+
+	/* everything is good - enable the events and process */
+	perf_evlist__enable(kvm->evlist);
+
+	while (!done) {
+		int rc;
+
+		rc = perf_kvm__mmap_read(kvm);
+		if (rc < 0)
+			break;
+
+		err = perf_kvm__handle_timerfd(kvm);
+		if (err)
+			goto out;
+
+		done = perf_kvm__handle_stdin(&tc, &save);
+
+		if (!rc && !done)
+			err = poll(pollfds, nr_fds, 100);
+	}
+
+	perf_evlist__disable(kvm->evlist);
+
+	if (err == 0) {
+		sort_result(kvm);
+		print_result(kvm);
+	}
+
+out:
+	if (kvm->timerfd >= 0)
+		close(kvm->timerfd);
+
+	if (pollfds)
+		free(pollfds);
+
+	return err;
+}
+
+
+/* TO-DO: how to merge this with perf-stat */
+static int perf_kvm__open_counters(struct perf_kvm *kvm)
+{
+	struct perf_evsel *pos;
+	struct perf_evlist *evlist = kvm->evlist;
+	int err = 0;
+
+	/*
+	 * Note: exclude_{guest,host} do not apply here.
+	 *       This command processes KVM tracepoints form host only
+	 */
+	list_for_each_entry(pos, &evlist->entries, node) {
+		struct perf_event_attr *attr = &pos->attr;
+
+		attr->sample_type = 0;
+		attr->read_format = 0;
+
+		attr->sample_type |= PERF_SAMPLE_TID;
+		attr->sample_type |= PERF_SAMPLE_TIME;
+		attr->sample_type |= PERF_SAMPLE_CPU;
+		attr->sample_type |= PERF_SAMPLE_RAW;
+
+		if (evlist->nr_entries > 1) {
+			attr->sample_type |= PERF_SAMPLE_ID;
+			attr->read_format |= PERF_FORMAT_ID;
+		}
+
+		attr->sample_id_all = kvm->opts.sample_id_all_missing ? 0 : 1;
+		attr->sample_period = 1;
+		attr->comm = !pos->idx;
+
+		attr->watermark = 0;
+		attr->wakeup_events = 100;
+
+		/* will enable all once we are ready */
+		attr->disabled = 1;
+
+retry_sample_id:
+		attr->sample_id_all = kvm->opts.sample_id_all_missing ? 0 : 1;
+		if (perf_evsel__open(pos, evlist->cpus, evlist->threads) < 0) {
+			err = errno;
+
+			if (err == EPERM || err == EACCES) {
+				ui__error_paranoid();
+				goto out_err;
+			} else if ((err == EINVAL) &&
+				   !kvm->opts.sample_id_all_missing) {
+				/*
+				 * Old kernel, no attr->sample_id_type_all field
+				 */
+				kvm->opts.sample_id_all_missing = true;
+				goto retry_sample_id;
+			}
+
+			/*
+			 * should never happen since the event is validated
+			 * before adding to evlist.
+			 */
+			if (err == ENOENT) {
+				ui__error("The %s event is not supported.\n",
+					  perf_evsel__name(pos));
+				goto out_err;
+			} else if (err == EMFILE) {
+				ui__error("Too many events need to be opened.\n");
+				goto out_err;
+			}
+
+			ui__error("The sys_perf_event_open() syscall "
+				  "returned with %d (%s).  /bin/dmesg "
+				  "may provide additional information.\n",
+				  err, strerror(err));
+			goto out_err;
+		}
+	}
+
+	if (perf_evlist__mmap(evlist, kvm->opts.mmap_pages, false) < 0) {
+		ui__error("Failed to mmap with %d (%s)\n",
+			  errno, strerror(errno));
+		goto out_err;
+	}
+
+out_err:
+	return err;
 }
 
 static int read_events(struct perf_kvm *kvm)

@@ -746,30 +1203,13 @@ static int read_events(struct perf_kvm *kvm)
 	 * Do not use 'isa' recorded in kvm_exit tracepoint since it is not
 	 * traced in the old kernel.
 	 */
-	ret = get_cpu_isa(kvm->session);
-
+	ret = cpu_isa_config(kvm);
 	if (ret < 0)
 		return ret;
 
-	if (ret == 1) {
-		kvm->exit_reasons = vmx_exit_reasons;
-		kvm->exit_reasons_size = ARRAY_SIZE(vmx_exit_reasons);
-		kvm->exit_reasons_isa = "VMX";
-	}
-
 	return perf_session__process_events(kvm->session, &kvm->tool);
 }
 
-static bool verify_vcpu(int vcpu)
-{
-	if (vcpu != -1 && vcpu < 0) {
-		pr_err("Invalid vcpu:%d.\n", vcpu);
-		return false;
-	}
-
-	return true;
-}
-
 static int kvm_events_report_vcpu(struct perf_kvm *kvm)
 {
 	int ret = -EINVAL;

@@ -881,6 +1321,159 @@ static int kvm_events_report(struct perf_kvm *kvm, int argc, const char **argv)
 	return kvm_events_report_vcpu(kvm);
 }
 
+static int kvm_events_live(struct perf_kvm *kvm, int argc, const char **argv)
+{
+	struct perf_session *session = NULL;
+	char errbuf[BUFSIZ];
+	int err;
+	const struct option live_options[] = {
+		OPT_STRING('p', "pid", &kvm->opts.target.pid, "pid",
+			"record events on existing process id"),
+		OPT_STRING('t', "tid", &kvm->opts.target.tid, "tid",
+			"record events on existing thread id"),
+		OPT_STRING('C', "cpu", &kvm->opts.target.cpu_list, "cpu",
+			"list of host cpus to monitor"),
+		OPT_UINTEGER('m', "mmap-pages", &kvm->opts.mmap_pages,
+			"number of mmap data pages"),
+		OPT_INCR('v', "verbose", &verbose,
+			"be more verbose (show counter open errors, etc)"),
+		OPT_BOOLEAN('a', "all-cpus", &kvm->opts.target.system_wide,
+			"system-wide collection from all CPUs"),
+		OPT_UINTEGER('d', "display", &kvm->display_time,
+			"time in seconds between display updates"),
+		OPT_STRING(0, "event", &kvm->report_event, "report event",
+			"event for reporting: vmexit, mmio, ioport"),
+		OPT_INTEGER(0, "vcpu", &kvm->trace_vcpu,
+			"vcpu id to report"),
+		OPT_STRING('k', "key", &kvm->sort_key, "sort-key",
+			"key for sorting: sample(sort by samples number)"
+			" time (sort by avg time)"),
+		OPT_END()
+	};
+	const char * const live_usage[] = {
+		"perf kvm stat live [<options>]",
+		NULL
+	};
+
+
+	/* event handling */
+	kvm->tool.sample = process_sample_event;
+	kvm->tool.comm   = perf_event__process_comm;
+	kvm->tool.exit   = perf_event__process_exit;
+	kvm->tool.fork   = perf_event__process_fork,
+	kvm->tool.lost   = process_lost_event;
+	kvm->tool.ordered_samples = true;
+	perf_tool__fill_defaults(&kvm->tool);
+
+	/* set defaults */
+	kvm->display_time = 1;
+	kvm->opts.user_interval = 1;
+	kvm->opts.mmap_pages = 512;
+	kvm->opts.target.uses_mmap = true;
+
+	kvm->evlist = perf_evlist__new(NULL, NULL);
+	if (kvm->evlist == NULL)
+		return -ENOMEM;
+
+	symbol__init();
+	disable_buildid_cache();
+
+	if (argc) {
+		argc = parse_options(argc, argv, live_options,
+				     live_usage, 0);
+		if (argc)
+			usage_with_options(live_usage, live_options);
+	}
+
+	use_browser = 0;
+	setup_browser(false);
+
+	/*
+	 * target related setups
+	 */
+	if (perf_target__none(&kvm->opts.target))
+		kvm->opts.target.system_wide = true;
+
+	err = perf_target__validate(&kvm->opts.target);
+	if (err) {
+		perf_target__strerror(&kvm->opts.target, err, errbuf, BUFSIZ);
+		ui__warning("%s", errbuf);
+	}
+
+	err = perf_target__parse_uid(&kvm->opts.target);
+	if (err) {
+		int saved_errno = errno;
+
+		perf_target__strerror(&kvm->opts.target, err,
+				      errbuf, BUFSIZ);
+		ui__error("%s", errbuf);
+
+		err = -saved_errno;
+		goto out;
+	}
+
+	/*
+	 * generate the event list
+	 */
+	err = perf_evlist__add_tracepoints(kvm->evlist,
+					   kvm_events_tp,
+					   ARRAY_SIZE(kvm_events_tp));
+	if (err != 0)
+		goto out;
+
+	symbol_conf.nr_events = kvm->evlist->nr_entries;
+
+	if (perf_evlist__create_maps(kvm->evlist, &kvm->opts.target) < 0)
+		usage_with_options(live_usage, live_options);
+
+	/*
+	 * perf session
+	 */
+	session = perf_session__new(NULL, O_WRONLY, false, false, &kvm->tool);
+	if (session == NULL) {
+		err = -ENOMEM;
+		goto out;
+	}
+	session->evlist = kvm->evlist;
+	kvm->session = session;
+	perf_session__set_id_hdr_size(session);
+
+
+	/*
+	 * need to get pevent initialized
+	 */
+	err = perf_evlist__trace_init(kvm->evlist, session);
+	if (err != 0)
+		goto out;
+
+	if (perf_target__has_task(&kvm->opts.target))
+		perf_event__synthesize_thread_map(&kvm->tool,
+						  kvm->evlist->threads,
+						  perf_event__process,
+						  &session->host_machine);
+	else
+		perf_event__synthesize_threads(&kvm->tool, perf_event__process,
+					       &session->host_machine);
+
+
+	err = perf_kvm__open_counters(kvm);
+	if (err != 0)
+		goto out;
+
+	err = kvm_events_live_report(kvm);
+
+out:
+	exit_browser(0);
+
+	if (session)
+		perf_session__delete(session);
+	kvm->session = NULL;
+	perf_evlist__delete_maps(kvm->evlist);
+	perf_evlist__delete(kvm->evlist);
+
+	return err;
+}
+
 static void print_kvm_stat_usage(void)
 {
 	printf("Usage: perf kvm stat <command>\n\n");

@@ -888,6 +1481,7 @@ static void print_kvm_stat_usage(void)
 	printf("# Available commands:\n");
 	printf("\trecord: record kvm events\n");
 	printf("\treport: report statistical data of kvm events\n");
+	printf("\tlive:   live reporting of statistical data of kvm events\n");
 
 	printf("\nOtherwise, it is the alias of 'perf stat':\n");
 }

@@ -905,6 +1499,9 @@ static int kvm_cmd_stat(struct perf_kvm *kvm, int argc, const char **argv)
 	if (!strncmp(argv[1], "rep", 3))
 		return kvm_events_report(kvm, argc - 1 , argv + 1);
 
+	if (!strncmp(argv[1], "live", 4))
+		return kvm_events_live(kvm, argc - 1 , argv + 1);
+
 perf_stat:
 	return cmd_stat(argc, argv, NULL);
 }