1 files changed, 103 insertions, 0 deletions
diff --git a/src/smooth_refresh.h b/src/smooth_refresh.h
new file mode 100644
index 0000000..8dc1f97
--- /dev/null
+++ b/src/smooth_refresh.h
@@ -0,0 +1,103 @@
+/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+#ifndef _GSM_SMOOTH_REFRESH_H
+#define _GSM_SMOOTH_REFRESH_H
+
+#include <giomm.h>
+#include <glibmm.h>
+#include <string>
+
+#include "util.h"
+
+using std::string;
+
+
+
+class SmoothRefresh
+  : private procman::NonCopyable
+{
+  public:
+
+    /*
+      smooth_refresh_new
+
+      @config_interval : pointer to config_interval so we can observe
+      config_interval changes.
+
+      @return : initialized SmoothRefresh
+    */
+    SmoothRefresh(Glib::RefPtr<Gio::Settings> a_settings);
+
+    ~SmoothRefresh();
+
+    /*
+      smooth_refresh_reset
+
+      Resets state and re-read config_interval
+    */
+    void reset();
+
+    /*
+      smooth_refresh_get
+
+      Computes the new refresh_interval so that CPU usage is lower than
+      SMOOTH_REFRESH_PCPU.
+
+      @new_interval : where the new refresh_interval is stored.
+
+      @return : TRUE is refresh_interval has changed. The new refresh_interval
+      is stored in @new_interval. Else FALSE;
+    */
+    bool get(guint &new_interval);
+
+
+    static const string KEY;
+    static const bool KEY_DEFAULT_VALUE;
+
+  private:
+
+    unsigned get_own_cpu_usage();
+
+    void load_settings_value(Glib::ustring key);
+
+    /*
+      fuzzy logic:
+      - decrease refresh interval only if current CPU% and last CPU%
+      are higher than PCPU_LO
+      - increase refresh interval only if current CPU% and last CPU%
+      are higher than PCPU_HI
+
+    */
+
+    enum
+    {
+        PCPU_HI = 22,
+        PCPU_LO = 18
+    };
+
+    /*
+      -self : procman's PID (so we call getpid() only once)
+
+      -interval : current refresh interval
+
+      -config_interval : pointer to the configuration refresh interval.
+      Used to watch configuration changes
+
+      -interval >= -config_interval
+
+      -last_pcpu : to avoid spikes, the last CPU%. See PCPU_{LO,HI}
+
+      -last_total_time:
+      -last_cpu_time: Save last cpu and process times to compute CPU%
+    */
+
+    Glib::RefPtr<Gio::Settings> settings;
+    bool active;
+    sigc::connection connection;
+    guint interval;
+    unsigned  last_pcpu;
+    guint64 last_total_time;
+    guint64 last_cpu_time;
+};
+
+
+#endif /* _GSM_SMOOTH_REFRESH_H */