3 files changed, 133 insertions, 0 deletions
diff --git a/collectors/idlejitter.plugin/Makefile.am b/collectors/idlejitter.plugin/Makefile.am
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index 0000000..161784b
--- /dev/null
+++ b/collectors/idlejitter.plugin/Makefile.am
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+dist_noinst_DATA = \
+    README.md \
+    $(NULL)
diff --git a/collectors/idlejitter.plugin/README.md b/collectors/idlejitter.plugin/README.md
new file mode 100644
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+++ b/collectors/idlejitter.plugin/README.md
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+<!--
+title: "idlejitter.plugin"
+custom_edit_url: https://github.com/netdata/netdata/edit/master/collectors/idlejitter.plugin/README.md
+-->
+
+# idlejitter.plugin
+
+Idle jitter is a measure of delays in timing for user processes caused by scheduling limitations.
+
+## How Netdata measures idle jitter
+
+A thread is spawned that requests to sleep for 20000 microseconds (20ms).
+When the system wakes it up, it measures how many microseconds have passed.
+The difference between the requested and the actual duration of the sleep, is the idle jitter.
+This is done at most 50 times per second, to ensure we have a good average. 
+
+This number is useful:
+
+- In multimedia-streaming environments such as VoIP gateways, where the CPU jitter can affect the quality of the service.
+- On time servers and other systems that require very precise timing, where CPU jitter can actively interfere with timing precision.
+- On gaming systems, where CPU jitter can cause frame drops and stuttering.
+- In cloud infrastructure that can pause the VM or container for a small duration to perform operations at the host.
+
+## Charts
+
+idlejitter.plugin generates the idlejitter chart which measures CPU idle jitter in milliseconds lost per second. 
+
+## Configuration
+
+This chart is available without any configuration. 
+
+
diff --git a/collectors/idlejitter.plugin/plugin_idlejitter.c b/collectors/idlejitter.plugin/plugin_idlejitter.c
new file mode 100644
index 0000000..b6339cc
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+++ b/collectors/idlejitter.plugin/plugin_idlejitter.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "daemon/common.h"
+
+#define CPU_IDLEJITTER_SLEEP_TIME_MS 20
+
+static void cpuidlejitter_main_cleanup(void *ptr) {
+    worker_unregister();
+
+    struct netdata_static_thread *static_thread = (struct netdata_static_thread *)ptr;
+    static_thread->enabled = NETDATA_MAIN_THREAD_EXITING;
+
+    info("cleaning up...");
+
+    static_thread->enabled = NETDATA_MAIN_THREAD_EXITED;
+}
+
+void *cpuidlejitter_main(void *ptr) {
+    worker_register("IDLEJITTER");
+    worker_register_job_name(0, "measurements");
+
+    netdata_thread_cleanup_push(cpuidlejitter_main_cleanup, ptr);
+
+    usec_t sleep_ut = config_get_number("plugin:idlejitter", "loop time in ms", CPU_IDLEJITTER_SLEEP_TIME_MS) * USEC_PER_MS;
+    if(sleep_ut <= 0) {
+        config_set_number("plugin:idlejitter", "loop time in ms", CPU_IDLEJITTER_SLEEP_TIME_MS);
+        sleep_ut = CPU_IDLEJITTER_SLEEP_TIME_MS * USEC_PER_MS;
+    }
+
+    RRDSET *st = rrdset_create_localhost(
+            "system"
+            , "idlejitter"
+            , NULL
+            , "idlejitter"
+            , NULL
+            , "CPU Idle Jitter"
+            , "microseconds lost/s"
+            , "idlejitter.plugin"
+            , NULL
+            , NETDATA_CHART_PRIO_SYSTEM_IDLEJITTER
+            , localhost->rrd_update_every
+            , RRDSET_TYPE_AREA
+    );
+    RRDDIM *rd_min = rrddim_add(st, "min", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
+    RRDDIM *rd_max = rrddim_add(st, "max", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
+    RRDDIM *rd_avg = rrddim_add(st, "average", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
+
+    usec_t update_every_ut = localhost->rrd_update_every * USEC_PER_SEC;
+    struct timeval before, after;
+
+    while (!netdata_exit) {
+        int iterations = 0;
+        usec_t error_total = 0,
+                error_min = 0,
+                error_max = 0,
+                elapsed = 0;
+
+        while (elapsed < update_every_ut) {
+            now_monotonic_high_precision_timeval(&before);
+            worker_is_idle();
+            sleep_usec(sleep_ut);
+            worker_is_busy(0);
+            now_monotonic_high_precision_timeval(&after);
+
+            usec_t dt = dt_usec(&after, &before);
+            elapsed += dt;
+
+            usec_t error = dt - sleep_ut;
+            error_total += error;
+
+            if(unlikely(!iterations))
+                error_min = error;
+            else if(error < error_min)
+                error_min = error;
+
+            if(error > error_max)
+                error_max = error;
+
+            iterations++;
+        }
+
+        if(iterations) {
+            rrddim_set_by_pointer(st, rd_min, error_min);
+            rrddim_set_by_pointer(st, rd_max, error_max);
+            rrddim_set_by_pointer(st, rd_avg, error_total / iterations);
+            rrdset_done(st);
+        }
+    }
+
+    netdata_thread_cleanup_pop(1);
+    return NULL;
+}
+