From 5de46c6bac422263a050f652b931628f513a868a Mon Sep 17 00:00:00 2001
From: Sergei Semenchuk <binjip978@gmail.com>
Date: Tue, 28 Sep 2021 08:44:03 +0300
Subject: [PATCH] collect flag_info and bug_info only for one core (#2156)

Signed-off-by: binjip978 <binjip978@gmail.com>
---
 collector/cpu_linux.go            | 8 ++++++--
 collector/fixtures/e2e-output.txt | 4 ++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/collector/cpu_linux.go b/collector/cpu_linux.go
index cbd8f71d..6918f116 100644
--- a/collector/cpu_linux.go
+++ b/collector/cpu_linux.go
@@ -77,12 +77,12 @@ func NewCPUCollector(logger log.Logger) (Collector, error) {
 		),
 		cpuFlagsInfo: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "flag_info"),
-			"The `flags` field of CPU information from /proc/cpuinfo.",
+			"The `flags` field of CPU information from /proc/cpuinfo taken from the first core.",
 			[]string{"flag"}, nil,
 		),
 		cpuBugsInfo: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, cpuCollectorSubsystem, "bug_info"),
-			"The `bugs` field of CPU information from /proc/cpuinfo.",
+			"The `bugs` field of CPU information from /proc/cpuinfo taken from the first core.",
 			[]string{"bug"}, nil,
 		),
 		cpuGuest: prometheus.NewDesc(
@@ -167,7 +167,10 @@ func (c *cpuCollector) updateInfo(ch chan<- prometheus.Metric) error {
 			cpu.Microcode,
 			cpu.Stepping,
 			cpu.CacheSize)
+	}
 
+	if len(info) != 0 {
+		cpu := info[0]
 		if err := updateFieldInfo(cpu.Flags, c.cpuFlagsIncludeRegexp, c.cpuFlagsInfo, ch); err != nil {
 			return err
 		}
@@ -175,6 +178,7 @@ func (c *cpuCollector) updateInfo(ch chan<- prometheus.Metric) error {
 			return err
 		}
 	}
+
 	return nil
 }
 
diff --git a/collector/fixtures/e2e-output.txt b/collector/fixtures/e2e-output.txt
index ac254b5c..f892b839 100644
--- a/collector/fixtures/e2e-output.txt
+++ b/collector/fixtures/e2e-output.txt
@@ -247,7 +247,7 @@ node_cooling_device_cur_state{name="0",type="Processor"} 0
 # HELP node_cooling_device_max_state Maximum throttle state of the cooling device
 # TYPE node_cooling_device_max_state gauge
 node_cooling_device_max_state{name="0",type="Processor"} 3
-# HELP node_cpu_bug_info The `bugs` field of CPU information from /proc/cpuinfo.
+# HELP node_cpu_bug_info The `bugs` field of CPU information from /proc/cpuinfo taken from the first core.
 # TYPE node_cpu_bug_info gauge
 node_cpu_bug_info{bug="cpu_meltdown"} 1
 node_cpu_bug_info{bug="mds"} 1
@@ -259,7 +259,7 @@ node_cpu_core_throttles_total{core="0",package="0"} 5
 node_cpu_core_throttles_total{core="0",package="1"} 0
 node_cpu_core_throttles_total{core="1",package="0"} 0
 node_cpu_core_throttles_total{core="1",package="1"} 9
-# HELP node_cpu_flag_info The `flags` field of CPU information from /proc/cpuinfo.
+# HELP node_cpu_flag_info The `flags` field of CPU information from /proc/cpuinfo taken from the first core.
 # TYPE node_cpu_flag_info gauge
 node_cpu_flag_info{flag="aes"} 1
 node_cpu_flag_info{flag="avx"} 1