1 files changed, 151 insertions, 0 deletions
diff --git a/src/smooth_refresh.cpp b/src/smooth_refresh.cpp
new file mode 100644
index 0000000..45f28c1
--- /dev/null
+++ b/src/smooth_refresh.cpp
@@ -0,0 +1,151 @@
+/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+#include <config.h>
+
+#include <glib.h>
+
+#include <glibtop.h>
+#include <glibtop/proctime.h>
+#include <glibtop/cpu.h>
+
+#include "smooth_refresh.h"
+#include "application.h"
+#include "settings-keys.h"
+#include "util.h"
+
+
+const string SmoothRefresh::KEY(GSM_SETTING_SMOOTH_REFRESH);
+
+
+
+unsigned SmoothRefresh::get_own_cpu_usage()
+{
+    glibtop_cpu cpu;
+    glibtop_proc_time proctime;
+    guint64 elapsed;
+    unsigned usage = PCPU_LO;
+
+    glibtop_get_cpu (&cpu);
+    elapsed = cpu.total - this->last_total_time;
+
+    if (elapsed) { // avoid division by 0
+        glibtop_get_proc_time(&proctime, getpid());
+        usage = (proctime.rtime - this->last_cpu_time) * 100 / elapsed;
+        this->last_cpu_time = proctime.rtime;
+    }
+
+    usage = CLAMP(usage, 0, 100);
+
+    this->last_total_time = cpu.total;
+
+    return usage;
+}
+
+void SmoothRefresh::load_settings_value(Glib::ustring key)
+{
+    this->active = this->settings->get_boolean(key);
+
+    if (this->active)
+        procman_debug("smooth_refresh is enabled");
+}
+
+
+SmoothRefresh::SmoothRefresh(Glib::RefPtr<Gio::Settings> a_settings)
+    :
+    settings(a_settings),
+    active(false),
+    interval(0),
+    last_pcpu(0),
+    last_total_time(0ULL),
+    last_cpu_time(0ULL)
+{
+    this->connection = a_settings->signal_changed("smooth_refresh").connect([this](const Glib::ustring& key) { this->load_settings_value(key); });
+
+    this->reset();
+    this->load_settings_value(KEY);
+}
+
+
+
+void SmoothRefresh::reset()
+{
+    glibtop_cpu cpu;
+    glibtop_proc_time proctime;
+
+    glibtop_get_cpu(&cpu);
+    glibtop_get_proc_time(&proctime, getpid());
+
+    this->interval = GsmApplication::get()->config.update_interval;
+    this->last_pcpu = PCPU_LO;
+    this->last_total_time = cpu.total;
+    this->last_cpu_time = proctime.rtime;
+}
+
+
+
+SmoothRefresh::~SmoothRefresh()
+{
+    if (this->connection)
+        this->connection.disconnect();
+}
+
+
+
+bool
+SmoothRefresh::get(guint &new_interval)
+{
+    const unsigned config_interval = GsmApplication::get()->config.update_interval;
+
+    g_assert(this->interval >= config_interval);
+
+    if (not this->active)
+        return false;
+
+
+    const unsigned pcpu = this->get_own_cpu_usage();
+    /*
+      invariant: MAX_UPDATE_INTERVAL >= interval >= config_interval >= MIN_UPDATE_INTERVAL
+
+      i see 3 cases:
+
+      a) interval is too big (CPU usage < 10%)
+      -> increase interval
+
+      b) interval is too small (CPU usage > 10%) AND interval != config_interval
+      >
+      -> decrease interval
+
+      c) interval is config_interval (start or interval is perfect)
+
+    */
+
+    if (pcpu > PCPU_HI && this->last_pcpu > PCPU_HI)
+        new_interval = this->interval * 11 / 10;
+    else if (this->interval != config_interval && pcpu < PCPU_LO && this->last_pcpu < PCPU_LO)
+        new_interval = this->interval * 9 / 10;
+    else
+        new_interval = this->interval;
+
+    new_interval = CLAMP(new_interval, config_interval, config_interval * 2);
+    new_interval = CLAMP(new_interval, MIN_UPDATE_INTERVAL, MAX_UPDATE_INTERVAL);
+
+    bool changed = this->interval != new_interval;
+
+    if (changed)
+        this->interval = new_interval;
+
+    this->last_pcpu = pcpu;
+
+
+    if (changed) {
+        procman_debug("CPU usage is %3u%%, changed refresh_interval to %u (config %u)",
+                      this->last_pcpu,
+                      this->interval,
+                      config_interval);
+    }
+
+    g_assert(this->interval == new_interval);
+    g_assert(this->interval >= config_interval);
+
+    return changed;
+}
+