[PATCH 10/16 v2] perf kvm: add live mode

David Ahern
2013-05-26T00:28:25Z

perf kvm stat currently requires back to back record and report
commands to see stats. e.g,.

perf kvm stat record -p $pid -- sleep 1
perf kvm stat report

This is inconvenvient for on box monitoring of a VM. This patch
introduces a 'live' mode that in effect combines the record plus
report into one command. e.g., to monitor a single VM:

perf kvm stat live -p $pid

or all VMs:

perf kvm stat live

Same stats options for the record+report path work with the live mode.
Display rate defaults to 1 second and can be changed using the -d option.

v2:
removed ABSTIME arg from timerfd_settime as mentioned by Namhyung
only call perf_kvm__handle_stdin when poll returns activity.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
---
tools/perf/builtin-kvm.c | 603 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 577 insertions(+), 26 deletions(-)

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 7d14a3a..15fdf54 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -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 <lk/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>
@@ -82,6 +86,8 @@ struct exit_reasons_table {

struct perf_kvm_stat {
struct perf_tool tool;
+ struct perf_record_opts opts;
+ struct perf_evlist *evlist;
struct perf_session *session;

const char *file_name;
@@ -96,10 +102,16 @@ struct perf_kvm_stat {
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;
};

@@ -320,6 +332,23 @@ static void init_kvm_event_record(struct perf_kvm_stat *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);
@@ -472,7 +501,11 @@ static bool handle_end_event(struct perf_kvm_stat *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);
@@ -639,24 +672,60 @@ 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_stat *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_stat *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%");
@@ -683,6 +752,20 @@ static void print_result(struct perf_kvm_stat *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_stat *kvm = container_of(tool, struct perf_kvm_stat, tool);
+
+ kvm->lost_events++;
+ return 0;
}

static int process_sample_event(struct perf_tool *tool,
@@ -707,10 +790,20 @@ 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_stat *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;
@@ -718,10 +811,339 @@ 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)
+{
+ int nr_cpus;
+
+ if (vcpu != -1 && vcpu < 0) {
+ pr_err("Invalid vcpu:%d.\n", vcpu);
+ return false;
+ }
+
+ nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ if ((nr_cpus > 0) && (vcpu > nr_cpus - 1)) {
+ 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_stat *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_stat *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 __maybe_unused)
+{
+ done = 1;
+}
+
+static int perf_kvm__timerfd_create(struct perf_kvm_stat *kvm)
+{
+ struct itimerspec new_value;
+ int rc = -1;
+
+ kvm->timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+ if (kvm->timerfd < 0) {
+ pr_err("timerfd_create failed\n");
+ goto out;
+ }
+
+ new_value.it_value.tv_sec = kvm->display_time;
+ new_value.it_value.tv_nsec = 0;
+ new_value.it_interval.tv_sec = kvm->display_time;
+ new_value.it_interval.tv_nsec = 0;
+
+ if (timerfd_settime(kvm->timerfd, 0, &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_stat *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 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;
+
+ return 0;
+}
+
+static int kvm_events_live_report(struct perf_kvm_stat *kvm)
+{
+ struct pollfd *pollfds = NULL;
+ int nr_fds, nr_stdin, 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);
+ signal(SIGTERM, 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_stdin = nr_fds;
+ 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;
+
+ if (pollfds[nr_stdin].revents & POLLIN)
+ 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);
}

- return isa;
+out:
+ if (kvm->timerfd >= 0)
+ close(kvm->timerfd);
+
+ if (pollfds)
+ free(pollfds);
+
+ return err;
+}
+
+static int perf_kvm__open_counters(struct perf_kvm_stat *kvm)
+{
+ struct perf_evsel *pos;
+ struct perf_evlist *evlist = kvm->evlist;
+ char msg[512];
+
+ perf_evlist__config(evlist, &kvm->opts);
+
+ /*
+ * Note: exclude_{guest,host} do not apply here.
+ * This command processes KVM tracepoints from host only
+ */
+ list_for_each_entry(pos, &evlist->entries, node) {
+ struct perf_event_attr *attr = &pos->attr;
+
+ attr->sample_type |= PERF_SAMPLE_TID;
+ attr->sample_type |= PERF_SAMPLE_TIME;
+ attr->sample_type |= PERF_SAMPLE_CPU;
+ attr->sample_type |= PERF_SAMPLE_RAW;
+
+ attr->sample_period = 1;
+
+ attr->watermark = 0;
+ attr->wakeup_events = 1000;
+
+ /* will enable all once we are ready */
+ attr->disabled = 1;
+
+try_again:
+ if (perf_evsel__open(pos, evlist->cpus, evlist->threads) < 0) {
+ if (perf_evsel__fallback(pos, errno, msg, sizeof(msg))) {
+ if (verbose)
+ ui__warning("%s\n", msg);
+ goto try_again;
+ }
+
+ perf_evsel__open_strerror(pos, &kvm->opts.target,
+ errno, msg, sizeof(msg));
+ ui__error("%s\n", msg);
+ 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;
+ }
+
+ return 0;
+
+out_err:
+ return -1;
}

static int read_events(struct perf_kvm_stat *kvm)
@@ -749,30 +1171,13 @@ static int read_events(struct perf_kvm_stat *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_stat *kvm)
{
int ret = -EINVAL;
@@ -886,6 +1291,148 @@ kvm_events_report(struct perf_kvm_stat *kvm, int argc, const char **argv)
return kvm_events_report_vcpu(kvm);
}

+static int kvm_events_live(struct perf_kvm_stat *kvm,
+ int argc, const char **argv)
+{
+ 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->opts.target.uid_str = NULL;
+ kvm->opts.target.uid = UINT_MAX;
+
+ symbol__init();
+ disable_buildid_cache();
+
+ use_browser = 0;
+ setup_browser(false);
+
+ if (argc) {
+ argc = parse_options(argc, argv, live_options,
+ live_usage, 0);
+ if (argc)
+ usage_with_options(live_usage, live_options);
+ }
+
+ /*
+ * target related setups
+ */
+ err = perf_target__validate(&kvm->opts.target);
+ if (err) {
+ perf_target__strerror(&kvm->opts.target, err, errbuf, BUFSIZ);
+ ui__warning("%s", errbuf);
+ }
+
+ if (perf_target__none(&kvm->opts.target))
+ kvm->opts.target.system_wide = true;
+
+
+ /*
+ * generate the event list
+ */
+ kvm->evlist = perf_evlist__new();
+ if (kvm->evlist == NULL)
+ return -ENOMEM;
+
+ 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
+ */
+ kvm->session = perf_session__new(NULL, O_WRONLY, false, false, &kvm->tool);
+ if (kvm->session == NULL) {
+ err = -ENOMEM;
+ goto out;
+ }
+ kvm->session->evlist = kvm->evlist;
+ perf_session__set_id_hdr_size(kvm->session);
+
+ /*
+ * need to get pevent initialized
+ */
+ err = perf_evlist__trace_init(kvm->evlist, kvm->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,
+ &kvm->session->machines.host);
+ else
+ perf_event__synthesize_threads(&kvm->tool, perf_event__process,
+ &kvm->session->machines.host);
+
+
+ err = perf_kvm__open_counters(kvm);
+ if (err)
+ goto out;
+
+ err = kvm_events_live_report(kvm);
+
+out:
+ exit_browser(0);
+
+ if (kvm->session)
+ perf_session__delete(kvm->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");
@@ -893,6 +1440,7 @@ 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");
}
@@ -922,6 +1470,9 @@ static int kvm_cmd_stat(const char *file_name, 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);
}
--
1.7.10.1