system-stats: Run as part of worker process.

[openvswitch] / vswitchd / system-stats.c

diff --git a/vswitchd/system-stats.c b/vswitchd/system-stats.c
index 4dc2723c23521b9a50cba1ba0f3aaf45a9de4c60..e0937a3931b5570326e5fcd2e9bb99e55faa689c 100644 (file)
--- a/vswitchd/system-stats.c
+++ b/vswitchd/system-stats.c
@@ -35,10 +35,14 @@
 #include "daemon.h"
 #include "dirs.h"
 #include "dynamic-string.h"
+#include "json.h"
+#include "ofpbuf.h"
+#include "poll-loop.h"
 #include "shash.h"
 #include "smap.h"
 #include "timeval.h"
 #include "vlog.h"
+#include "worker.h"
 
 VLOG_DEFINE_THIS_MODULE(system_stats);
 
@@ -490,13 +494,155 @@ get_filesys_stats(struct smap *stats OVS_UNUSED)
     ds_destroy(&s);
 #endif  /* HAVE_SETMNTENT && HAVE_STATVFS */
 }
+\f
+#define SYSTEM_STATS_INTERVAL (5 * 1000) /* In milliseconds. */
 
+/* Whether the client wants us to report system stats. */
+static bool enabled;
+
+static enum {
+    S_DISABLED,                 /* Not enabled, nothing going on. */
+    S_WAITING,                  /* Sleeping for SYSTEM_STATS_INTERVAL ms. */
+    S_REQUEST_SENT,             /* Sent a request to worker. */
+    S_REPLY_RECEIVED            /* Received a reply from worker. */
+} state;
+
+/* In S_WAITING state: the next time to wake up.
+ * In other states: not meaningful. */
+static long long int next_refresh;
+
+/* In S_REPLY_RECEIVED: the stats that have just been received.
+ * In other states: not meaningful. */
+static struct smap *received_stats;
+
+static worker_request_func system_stats_request_cb;
+static worker_reply_func system_stats_reply_cb;
+
+/* Enables or disables system stats collection, according to 'new_enable'.
+ *
+ * Even if system stats are disabled, the caller should still periodically call
+ * system_stats_run(). */
 void
-get_system_stats(struct smap *stats)
+system_stats_enable(bool new_enable)
+{
+    if (new_enable != enabled) {
+        if (new_enable) {
+            if (state == S_DISABLED) {
+                state = S_WAITING;
+                next_refresh = time_msec();
+            }
+        } else {
+            if (state == S_WAITING) {
+                state = S_DISABLED;
+            }
+        }
+        enabled = new_enable;
+    }
+}
+
+/* Tries to obtain a new snapshot of system stats every SYSTEM_STATS_INTERVAL
+ * milliseconds.
+ *
+ * When a new snapshot is available (which only occurs if system stats are
+ * enabled), returns it as an smap owned by the caller.  The caller must use
+ * both smap_destroy() and free() to complete free the returned data.
+ *
+ * When no new snapshot is available, returns NULL. */
+struct smap *
+system_stats_run(void)
 {
-    get_cpu_cores(stats);
-    get_load_average(stats);
-    get_memory_stats(stats);
-    get_process_stats(stats);
-    get_filesys_stats(stats);
+    switch (state) {
+    case S_DISABLED:
+        break;
+
+    case S_WAITING:
+        if (time_msec() >= next_refresh) {
+            worker_request(NULL, 0, NULL, 0, system_stats_request_cb,
+                           system_stats_reply_cb, NULL);
+            state = S_REQUEST_SENT;
+        }
+        break;
+
+    case S_REQUEST_SENT:
+        break;
+
+    case S_REPLY_RECEIVED:
+        if (enabled) {
+            state = S_WAITING;
+            next_refresh = time_msec() + SYSTEM_STATS_INTERVAL;
+            return received_stats;
+        } else {
+            smap_destroy(received_stats);
+            free(received_stats);
+            state = S_DISABLED;
+        }
+        break;
+    }
+
+    return NULL;
+}
+
+/* Causes poll_block() to wake up when system_stats_run() needs to be
+ * called. */
+void
+system_stats_wait(void)
+{
+    switch (state) {
+    case S_DISABLED:
+        break;
+
+    case S_WAITING:
+        poll_timer_wait_until(next_refresh);
+        break;
+
+    case S_REQUEST_SENT:
+        /* Someone else should be calling worker_wait() to wake up when the
+         * reply arrives, otherwise there's a bug. */
+        break;
+
+    case S_REPLY_RECEIVED:
+        poll_immediate_wake();
+        break;
+    }
+}
+
+static void
+system_stats_request_cb(struct ofpbuf *request OVS_UNUSED,
+                        const int fds[] OVS_UNUSED, size_t n_fds OVS_UNUSED)
+{
+    struct smap stats;
+    struct json *json;
+    char *s;
+
+    smap_init(&stats);
+    get_cpu_cores(&stats);
+    get_load_average(&stats);
+    get_memory_stats(&stats);
+    get_process_stats(&stats);
+    get_filesys_stats(&stats);
+
+    json = smap_to_json(&stats);
+    s = json_to_string(json, 0);
+    worker_reply(s, strlen(s) + 1, NULL, 0);
+
+    free(s);
+    json_destroy(json);
+    smap_destroy(&stats);
+}
+
+static void
+system_stats_reply_cb(struct ofpbuf *reply,
+                      const int fds[] OVS_UNUSED, size_t n_fds OVS_UNUSED,
+                      void *aux OVS_UNUSED)
+{
+    struct json *json = json_from_string(reply->data);
+
+    received_stats = xmalloc(sizeof *received_stats);
+    smap_init(received_stats);
+    smap_from_json(received_stats, json);
+
+    assert(state == S_REQUEST_SENT);
+    state = S_REPLY_RECEIVED;
+
+    json_destroy(json);
 }