src/collectors/proc.plugin/proc_softirqs.c
// SPDX-License-Identifier: GPL-3.0-or-later
#include "plugin_proc.h"
#define PLUGIN_PROC_MODULE_SOFTIRQS_NAME "/proc/softirqs"
#define MAX_INTERRUPT_NAME 50
struct cpu_interrupt {
unsigned long long value;
RRDDIM *rd;
};
struct interrupt {
int used;
char *id;
char name[MAX_INTERRUPT_NAME + 1];
RRDDIM *rd;
unsigned long long total;
struct cpu_interrupt cpu[];
};
// since each interrupt is variable in size
// we use this to calculate its record size
#define recordsize(cpus) (sizeof(struct interrupt) + ((cpus) * sizeof(struct cpu_interrupt)))
// given a base, get a pointer to each record
#define irrindex(base, line, cpus) ((struct interrupt *)&((char *)(base))[(line) * recordsize(cpus)])
static inline struct interrupt *get_interrupts_array(size_t lines, int cpus) {
static struct interrupt *irrs = NULL;
static size_t allocated = 0;
if(unlikely(lines != allocated)) {
uint32_t l;
int c;
irrs = (struct interrupt *)reallocz(irrs, lines * recordsize(cpus));
// reset all interrupt RRDDIM pointers as any line could have shifted
for(l = 0; l < lines ;l++) {
struct interrupt *irr = irrindex(irrs, l, cpus);
irr->rd = NULL;
irr->name[0] = '\0';
for(c = 0; c < cpus ;c++)
irr->cpu[c].rd = NULL;
}
allocated = lines;
}
return irrs;
}
int do_proc_softirqs(int update_every, usec_t dt) {
(void)dt;
static procfile *ff = NULL;
static int cpus = -1, do_per_core = CONFIG_BOOLEAN_INVALID;
struct interrupt *irrs = NULL;
if(unlikely(do_per_core == CONFIG_BOOLEAN_INVALID))
do_per_core = config_get_boolean_ondemand("plugin:proc:/proc/softirqs", "interrupts per core", CONFIG_BOOLEAN_NO);
if(unlikely(!ff)) {
char filename[FILENAME_MAX + 1];
snprintfz(filename, FILENAME_MAX, "%s%s", netdata_configured_host_prefix, "/proc/softirqs");
ff = procfile_open(config_get("plugin:proc:/proc/softirqs", "filename to monitor", filename), " \t:", PROCFILE_FLAG_DEFAULT);
if(unlikely(!ff)) return 1;
}
ff = procfile_readall(ff);
if(unlikely(!ff)) return 0; // we return 0, so that we will retry to open it next time
size_t lines = procfile_lines(ff), l;
size_t words = procfile_linewords(ff, 0);
if(unlikely(!lines)) {
collector_error("Cannot read /proc/softirqs, zero lines reported.");
return 1;
}
// find how many CPUs are there
if(unlikely(cpus == -1)) {
uint32_t w;
cpus = 0;
for(w = 0; w < words ; w++) {
if(likely(strncmp(procfile_lineword(ff, 0, w), "CPU", 3) == 0))
cpus++;
}
}
if(unlikely(!cpus)) {
collector_error("PLUGIN: PROC_SOFTIRQS: Cannot find the number of CPUs in /proc/softirqs");
return 1;
}
// allocate the size we need;
irrs = get_interrupts_array(lines, cpus);
irrs[0].used = 0;
// loop through all lines
for(l = 1; l < lines ;l++) {
struct interrupt *irr = irrindex(irrs, l, cpus);
irr->used = 0;
irr->total = 0;
words = procfile_linewords(ff, l);
if(unlikely(!words)) continue;
irr->id = procfile_lineword(ff, l, 0);
if(unlikely(!irr->id || !irr->id[0])) continue;
int c;
for(c = 0; c < cpus ;c++) {
if(likely((c + 1) < (int)words))
irr->cpu[c].value = str2ull(procfile_lineword(ff, l, (uint32_t) (c + 1)), NULL);
else
irr->cpu[c].value = 0;
irr->total += irr->cpu[c].value;
}
strncpyz(irr->name, irr->id, MAX_INTERRUPT_NAME);
irr->used = 1;
}
// --------------------------------------------------------------------
static RRDSET *st_system_softirqs = NULL;
if(unlikely(!st_system_softirqs)) {
st_system_softirqs = rrdset_create_localhost(
"system"
, "softirqs"
, NULL
, "softirqs"
, NULL
, "System softirqs"
, "softirqs/s"
, PLUGIN_PROC_NAME
, PLUGIN_PROC_MODULE_SOFTIRQS_NAME
, NETDATA_CHART_PRIO_SYSTEM_SOFTIRQS
, update_every
, RRDSET_TYPE_STACKED
);
}
for(l = 0; l < lines ;l++) {
struct interrupt *irr = irrindex(irrs, l, cpus);
if(irr->used && irr->total) {
// some interrupt may have changed without changing the total number of lines
// if the same number of interrupts have been added and removed between two
// calls of this function.
if(unlikely(!irr->rd || strncmp(irr->name, rrddim_name(irr->rd), MAX_INTERRUPT_NAME) != 0)) {
irr->rd = rrddim_add(st_system_softirqs, irr->id, irr->name, 1, 1, RRD_ALGORITHM_INCREMENTAL);
rrddim_reset_name(st_system_softirqs, irr->rd, irr->name);
// also reset per cpu RRDDIMs to avoid repeating strncmp() in the per core loop
if(likely(do_per_core != CONFIG_BOOLEAN_NO)) {
int c;
for(c = 0; c < cpus; c++) irr->cpu[c].rd = NULL;
}
}
rrddim_set_by_pointer(st_system_softirqs, irr->rd, irr->total);
}
}
rrdset_done(st_system_softirqs);
// --------------------------------------------------------------------
if(do_per_core != CONFIG_BOOLEAN_NO) {
static RRDSET **core_st = NULL;
static int old_cpus = 0;
if(old_cpus < cpus) {
core_st = reallocz(core_st, sizeof(RRDSET *) * cpus);
memset(&core_st[old_cpus], 0, sizeof(RRDSET *) * (cpus - old_cpus));
old_cpus = cpus;
}
int c;
for(c = 0; c < cpus ; c++) {
if(unlikely(!core_st[c])) {
// find if everything is just zero
unsigned long long core_sum = 0;
for (l = 0; l < lines; l++) {
struct interrupt *irr = irrindex(irrs, l, cpus);
if (unlikely(!irr->used)) continue;
core_sum += irr->cpu[c].value;
}
if (unlikely(core_sum == 0)) continue; // try next core
char id[50 + 1];
snprintfz(id, sizeof(id) - 1, "cpu%d_softirqs", c);
char title[100 + 1];
snprintfz(title, sizeof(title) - 1, "CPU softirqs");
core_st[c] = rrdset_create_localhost(
"cpu"
, id
, NULL
, "softirqs"
, "cpu.softirqs"
, title
, "softirqs/s"
, PLUGIN_PROC_NAME
, PLUGIN_PROC_MODULE_SOFTIRQS_NAME
, NETDATA_CHART_PRIO_SOFTIRQS_PER_CORE + c
, update_every
, RRDSET_TYPE_STACKED
);
char core[50+1];
snprintfz(core, sizeof(core) - 1, "cpu%d", c);
rrdlabels_add(core_st[c]->rrdlabels, "cpu", core, RRDLABEL_SRC_AUTO);
}
for(l = 0; l < lines ;l++) {
struct interrupt *irr = irrindex(irrs, l, cpus);
if(irr->used && (do_per_core == CONFIG_BOOLEAN_YES || irr->cpu[c].value)) {
if(unlikely(!irr->cpu[c].rd)) {
irr->cpu[c].rd = rrddim_add(core_st[c], irr->id, irr->name, 1, 1, RRD_ALGORITHM_INCREMENTAL);
rrddim_reset_name(core_st[c], irr->cpu[c].rd, irr->name);
}
rrddim_set_by_pointer(core_st[c], irr->cpu[c].rd, irr->cpu[c].value);
}
}
rrdset_done(core_st[c]);
}
}
return 0;
}