feat(cgroups.plugin): add "CPU Time Relative Share" chart (#12741)

collectors/cgroups.plugin/sys_fs_cgroup.c

@@ -14,6 +14,7 @@ static long system_page_size = 4096; // system will be queried via sysconf() in
 static int cgroup_enable_cpuacct_stat = CONFIG_BOOLEAN_AUTO;
 static int cgroup_enable_cpuacct_usage = CONFIG_BOOLEAN_AUTO;
 static int cgroup_enable_cpuacct_cpu_throttling = CONFIG_BOOLEAN_YES;
+static int cgroup_enable_cpuacct_cpu_shares = CONFIG_BOOLEAN_NO;
 static int cgroup_enable_memory = CONFIG_BOOLEAN_AUTO;
 static int cgroup_enable_detailed_memory = CONFIG_BOOLEAN_AUTO;
 static int cgroup_enable_memory_failcnt = CONFIG_BOOLEAN_AUTO;
@@ -283,6 +284,7 @@ void read_cgroup_plugin_configuration() {
     cgroup_enable_cpuacct_stat = config_get_boolean_ondemand("plugin:cgroups", "enable cpuacct stat (total CPU)", cgroup_enable_cpuacct_stat);
     cgroup_enable_cpuacct_usage = config_get_boolean_ondemand("plugin:cgroups", "enable cpuacct usage (per core CPU)", cgroup_enable_cpuacct_usage);
     cgroup_enable_cpuacct_cpu_throttling = config_get_boolean_ondemand("plugin:cgroups", "enable cpuacct cpu throttling", cgroup_enable_cpuacct_cpu_throttling);
+    cgroup_enable_cpuacct_cpu_shares = config_get_boolean_ondemand("plugin:cgroups", "enable cpuacct cpu shares", cgroup_enable_cpuacct_cpu_shares);
 
     cgroup_enable_memory = config_get_boolean_ondemand("plugin:cgroups", "enable memory", cgroup_enable_memory);
     cgroup_enable_detailed_memory = config_get_boolean_ondemand("plugin:cgroups", "enable detailed memory", cgroup_enable_detailed_memory);
@@ -707,6 +709,17 @@ struct cpuacct_cpu_throttling {
     unsigned long long nr_throttled_perc;
 };
 
+// https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/resource_management_guide/sec-cpu#sect-cfs
+// https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_monitoring_and_updating_the_kernel/using-cgroups-v2-to-control-distribution-of-cpu-time-for-applications_managing-monitoring-and-updating-the-kernel#proc_controlling-distribution-of-cpu-time-for-applications-by-adjusting-cpu-weight_using-cgroups-v2-to-control-distribution-of-cpu-time-for-applications
+struct cpuacct_cpu_shares {
+    int updated;
+    int enabled; // CONFIG_BOOLEAN_YES or CONFIG_BOOLEAN_AUTO
+
+    char *filename;
+
+    unsigned long long shares;
+};
+
 struct cgroup_network_interface {
     const char *host_device;
     const char *container_device;
@@ -736,6 +749,7 @@ struct cgroup {
     struct cpuacct_stat cpuacct_stat;
     struct cpuacct_usage cpuacct_usage;
     struct cpuacct_cpu_throttling cpuacct_cpu_throttling;
+    struct cpuacct_cpu_shares cpuacct_cpu_shares;
 
     struct memory memory;
 
@@ -760,6 +774,7 @@ struct cgroup {
     RRDSET *st_cpu_per_core;
     RRDSET *st_cpu_nr_throttled;
     RRDSET *st_cpu_throttled_time;
+    RRDSET *st_cpu_shares;
 
     RRDSET *st_mem;
     RRDSET *st_mem_utilization;
@@ -1031,6 +1046,24 @@ static inline void cgroup2_read_cpuacct_cpu_stat(struct cpuacct_stat *cp, struct
     }
 }
 
+static inline void cgroup_read_cpuacct_cpu_shares(struct cpuacct_cpu_shares *cp) {
+    if (unlikely(!cp->filename)) {
+        return;
+    }
+
+    if (unlikely(read_single_number_file(cp->filename, &cp->shares))) {
+        cp->updated = 0;
+        cgroups_check = 1;
+        return;
+    }
+
+    cp->updated = 1;
+    if (unlikely((cp->enabled == CONFIG_BOOLEAN_AUTO)) &&
+        (cp->shares || netdata_zero_metrics_enabled == CONFIG_BOOLEAN_YES)) {
+        cp->enabled = CONFIG_BOOLEAN_YES;
+    }
+}
+
 static inline void cgroup_read_cpuacct_usage(struct cpuacct_usage *ca) {
     static procfile *ff = NULL;
 
@@ -1402,6 +1435,7 @@ static inline void cgroup_read(struct cgroup *cg) {
         cgroup_read_cpuacct_stat(&cg->cpuacct_stat);
         cgroup_read_cpuacct_usage(&cg->cpuacct_usage);
         cgroup_read_cpuacct_cpu_stat(&cg->cpuacct_cpu_throttling);
+        cgroup_read_cpuacct_cpu_shares(&cg->cpuacct_cpu_shares);
         cgroup_read_memory(&cg->memory, 0);
         cgroup_read_blkio(&cg->io_service_bytes);
         cgroup_read_blkio(&cg->io_serviced);
@@ -1415,6 +1449,7 @@ static inline void cgroup_read(struct cgroup *cg) {
         cgroup2_read_blkio(&cg->io_service_bytes, 0);
         cgroup2_read_blkio(&cg->io_serviced, 4);
         cgroup2_read_cpuacct_cpu_stat(&cg->cpuacct_stat, &cg->cpuacct_cpu_throttling);
+        cgroup_read_cpuacct_cpu_shares(&cg->cpuacct_cpu_shares);
         cgroup2_read_pressure(&cg->cpu_pressure);
         cgroup2_read_pressure(&cg->io_pressure);
         cgroup2_read_pressure(&cg->memory_pressure);
@@ -1767,6 +1802,7 @@ static inline void cgroup_free(struct cgroup *cg) {
     if(cg->st_cpu_per_core)          rrdset_is_obsolete(cg->st_cpu_per_core);
     if(cg->st_cpu_nr_throttled)      rrdset_is_obsolete(cg->st_cpu_nr_throttled);
     if(cg->st_cpu_throttled_time)    rrdset_is_obsolete(cg->st_cpu_throttled_time);
+    if(cg->st_cpu_shares)            rrdset_is_obsolete(cg->st_cpu_shares);
     if(cg->st_mem)                   rrdset_is_obsolete(cg->st_mem);
     if(cg->st_writeback)             rrdset_is_obsolete(cg->st_writeback);
     if(cg->st_mem_activity)          rrdset_is_obsolete(cg->st_mem_activity);
@@ -1795,6 +1831,7 @@ static inline void cgroup_free(struct cgroup *cg) {
     freez(cg->cpuacct_stat.filename);
     freez(cg->cpuacct_usage.filename);
     freez(cg->cpuacct_cpu_throttling.filename);
+    freez(cg->cpuacct_cpu_shares.filename);
 
     arl_free(cg->memory.arl_base);
     freez(cg->memory.filename_detailed);
@@ -2021,6 +2058,18 @@ static inline void update_filenames()
                 else
                     debug(D_CGROUP, "cpu.stat file for cgroup '%s': '%s' does not exist.", cg->id, filename);
             }
+            if (unlikely(
+                    cgroup_enable_cpuacct_cpu_shares && !cg->cpuacct_cpu_shares.filename &&
+                    !(cg->options & CGROUP_OPTIONS_SYSTEM_SLICE_SERVICE))) {
+                snprintfz(filename, FILENAME_MAX, "%s%s/cpu.shares", cgroup_cpuacct_base, cg->id);
+                if (likely(stat(filename, &buf) != -1)) {
+                    cg->cpuacct_cpu_shares.filename = strdupz(filename);
+                    cg->cpuacct_cpu_shares.enabled = cgroup_enable_cpuacct_cpu_shares;
+                    debug(
+                        D_CGROUP, "cpu.shares filename for cgroup '%s': '%s'", cg->id, cg->cpuacct_cpu_shares.filename);
+                } else
+                    debug(D_CGROUP, "cpu.shares file for cgroup '%s': '%s' does not exist.", cg->id, filename);
+            }
 
             if(unlikely((cgroup_enable_detailed_memory || cgroup_used_memory) && !cg->memory.filename_detailed && (cgroup_used_memory || cgroup_enable_systemd_services_detailed_memory || !(cg->options & CGROUP_OPTIONS_SYSTEM_SLICE_SERVICE)))) {
                 snprintfz(filename, FILENAME_MAX, "%s%s/memory.stat", cgroup_memory_base, cg->id);
@@ -2221,6 +2270,16 @@ static inline void update_filenames()
                 else
                     debug(D_CGROUP, "cpu.stat file for unified cgroup '%s': '%s' does not exist.", cg->id, filename);
             }
+            if (unlikely(cgroup_enable_cpuacct_cpu_shares && !cg->cpuacct_cpu_shares.filename)) {
+                snprintfz(filename, FILENAME_MAX, "%s%s/cpu.weight", cgroup_unified_base, cg->id);
+                if (likely(stat(filename, &buf) != -1)) {
+                    cg->cpuacct_cpu_shares.filename = strdupz(filename);
+                    cg->cpuacct_cpu_shares.enabled = cgroup_enable_cpuacct_cpu_shares;
+                    debug(D_CGROUP, "cpu.weight filename for cgroup '%s': '%s'", cg->id, cg->cpuacct_cpu_shares.filename);
+                } else
+                    debug(D_CGROUP, "cpu.weight file for cgroup '%s': '%s' does not exist.", cg->id, filename);
+            }
+
             if(unlikely((cgroup_enable_detailed_memory || cgroup_used_memory) && !cg->memory.filename_detailed && (cgroup_used_memory || cgroup_enable_systemd_services_detailed_memory || !(cg->options & CGROUP_OPTIONS_SYSTEM_SLICE_SERVICE)))) {
                 snprintfz(filename, FILENAME_MAX, "%s%s/memory.stat", cgroup_unified_base, cg->id);
                 if(likely(stat(filename, &buf) != -1)) {
@@ -3672,6 +3731,34 @@ void update_cgroup_charts(int update_every) {
             }
         }
 
+        if (likely(cg->cpuacct_cpu_shares.updated && cg->cpuacct_cpu_shares.enabled == CONFIG_BOOLEAN_YES)) {
+            if (unlikely(!cg->st_cpu_shares)) {
+                snprintfz(title, CHART_TITLE_MAX, "CPU Time Relative Share");
+
+                cg->st_cpu_shares = rrdset_create_localhost(
+                        cgroup_chart_type(type, cg->chart_id, RRD_ID_LENGTH_MAX)
+                        , "cpu_shares"
+                        , NULL
+                        , "cpu"
+                        , "cgroup.cpu_shares"
+                        , title
+                        , "shares"
+                        , PLUGIN_CGROUPS_NAME
+                        , PLUGIN_CGROUPS_MODULE_CGROUPS_NAME
+                        , cgroup_containers_chart_priority + 20
+                        , update_every
+                        , RRDSET_TYPE_LINE
+                );
+
+                rrdset_update_labels(cg->st_cpu_shares, cg->chart_labels);
+                rrddim_add(cg->st_cpu_shares, "shares", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
+            } else {
+                rrdset_next(cg->st_cpu_shares);
+                rrddim_set(cg->st_cpu_shares, "shares", cg->cpuacct_cpu_shares.shares);
+                rrdset_done(cg->st_cpu_shares);
+            }
+        }
+
         if(likely(cg->cpuacct_usage.updated && cg->cpuacct_usage.enabled == CONFIG_BOOLEAN_YES)) {
             char id[RRD_ID_LENGTH_MAX + 1];
             unsigned int i;
@@ -4461,6 +4548,10 @@ void *cgroups_main(void *ptr) {
 
     struct rusage thread;
 
+    if (getenv("KUBERNETES_SERVICE_HOST") != NULL && getenv("KUBERNETES_SERVICE_PORT") != NULL) {
+        cgroup_enable_cpuacct_cpu_shares = CONFIG_BOOLEAN_YES;
+    }
+
     // when ZERO, attempt to do it
     int vdo_cpu_netdata = config_get_boolean("plugin:cgroups", "cgroups plugin resource charts", 1);
 

web/gui/dashboard_info.js

@@ -4026,6 +4026,13 @@ netdataDashboard.context = {
         'When an application has used its allotted CPU quota for a given period, it gets throttled until the next period.'
     },
 
+    'cgroup.cpu_shares': {
+        info: '<p>The weight of each group living in the same hierarchy, that translates into the amount of CPU it is expected to get. '+
+        'The percentage of CPU assigned to the cgroup is the value of shares divided by the sum of all shares in all cgroups in the same level.</p>'+
+        '<p>For example, tasks in two cgroups that have <b>cpu.shares</b> set to 100 will receive equal CPU time, '+
+        'but tasks in a cgroup that has <b>cpu.shares</b> set to 200 receive twice the CPU time of tasks in a cgroup where <b>cpu.shares</b> is set to 100.</p>'
+    },
+
     'cgroup.cpu_per_core': {
         info: 'Total CPU utilization per core within the system-wide CPU resources.'
     },