From b941a24e27742bf93ddf40b054aed854cad0e0ab Mon Sep 17 00:00:00 2001
From: Dean Chen <862469039@qq.com>
Date: Mon, 20 Jul 2026 23:33:18 +0500
Subject: [PATCH] collector/cpu: avoid frequency_hertz clash with cpufreq

Both collectors export node_cpu_frequency_hertz, but with different
help text and labels. When cpu.info and cpufreq run together (the
common case), Prometheus gather fails with inconsistent help strings.

Only fall back to /proc/cpuinfo when the cpufreq collector is disabled.
Drop the overlapping samples from the e2e fixture.

Fixes #3689

Signed-off-by: Dean Chen <862469039@qq.com>
---
 collector/cpu_linux.go            |  5 ++++-
 collector/fixtures/e2e-output.txt | 10 ----------
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/collector/cpu_linux.go b/collector/cpu_linux.go
index f7b0c3ef1f..780edaa1a4 100644
--- a/collector/cpu_linux.go
+++ b/collector/cpu_linux.go
@@ -219,10 +219,13 @@ func (c *cpuCollector) updateInfo(ch chan<- prometheus.Metric) error {
 			cpu.CacheSize)
 	}
 
+	// Avoid clashing with the cpufreq collector, which exports the same
+	// metric name with a different help string and label set. Only use
+	// /proc/cpuinfo when cpufreq is disabled.
 	cpuFreqEnabled, ok := collectorState["cpufreq"]
 	if !ok || cpuFreqEnabled == nil {
 		c.logger.Debug("cpufreq key missing or nil value in collectorState map")
-	} else if *cpuFreqEnabled {
+	} else if !*cpuFreqEnabled {
 		for _, cpu := range info {
 			ch <- prometheus.MustNewConstMetric(c.cpuFrequencyHz,
 				prometheus.GaugeValue,
diff --git a/collector/fixtures/e2e-output.txt b/collector/fixtures/e2e-output.txt
index 141cb76c3a..5709dd51dd 100644
--- a/collector/fixtures/e2e-output.txt
+++ b/collector/fixtures/e2e-output.txt
@@ -902,16 +902,6 @@ node_cpu_flag_info{flag="aes"} 1
 node_cpu_flag_info{flag="avx"} 1
 node_cpu_flag_info{flag="avx2"} 1
 node_cpu_flag_info{flag="constant_tsc"} 1
-# HELP node_cpu_frequency_hertz CPU frequency in hertz from /proc/cpuinfo.
-# TYPE node_cpu_frequency_hertz gauge
-node_cpu_frequency_hertz{core="0",cpu="0",package="0"} 7.99998e+08
-node_cpu_frequency_hertz{core="0",cpu="4",package="0"} 7.99989e+08
-node_cpu_frequency_hertz{core="1",cpu="1",package="0"} 8.00037e+08
-node_cpu_frequency_hertz{core="1",cpu="5",package="0"} 8.00083e+08
-node_cpu_frequency_hertz{core="2",cpu="2",package="0"} 8.0001e+08
-node_cpu_frequency_hertz{core="2",cpu="6",package="0"} 8.00017e+08
-node_cpu_frequency_hertz{core="3",cpu="3",package="0"} 8.00028e+08
-node_cpu_frequency_hertz{core="3",cpu="7",package="0"} 8.0003e+08
 # HELP node_cpu_guest_seconds_total Seconds the CPUs spent in guests (VMs) for each mode.
 # TYPE node_cpu_guest_seconds_total counter
 node_cpu_guest_seconds_total{cpu="0",mode="nice"} 0.01