pressure: Fix missing IRQ on older kernels

Fix "no data" error on kernels that support some PSI status, but don't
yet have IRQ presure metrics. Only report "no data" error if `pressure`
is enabled and no PSI metrics were found.

Fixes: https://github.com/prometheus/node_exporter/issues/3259

Signed-off-by: Ben Kochie <superq@gmail.com>
This commit is contained in:
Ben Kochie 2025-03-03 19:19:43 +01:00
parent 0c10545e8d
commit 17e4c71d05
No known key found for this signature in database
GPG key ID: C646B23C9E3245F1

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@ -27,8 +27,15 @@ import (
"github.com/prometheus/procfs" "github.com/prometheus/procfs"
) )
const (
psiResourceCPU = "cpu"
psiResourceIO = "io"
psiResourceMemory = "memory"
psiResourceIRQ = "irq"
)
var ( var (
psiResources = []string{"cpu", "io", "memory", "irq"} psiResources = []string{psiResourceCPU, psiResourceIO, psiResourceMemory, psiResourceIRQ}
) )
type pressureStatsCollector struct { type pressureStatsCollector struct {
@ -93,13 +100,18 @@ func NewPressureStatsCollector(logger *slog.Logger) (Collector, error) {
// Update calls procfs.NewPSIStatsForResource for the different resources and updates the values // Update calls procfs.NewPSIStatsForResource for the different resources and updates the values
func (c *pressureStatsCollector) Update(ch chan<- prometheus.Metric) error { func (c *pressureStatsCollector) Update(ch chan<- prometheus.Metric) error {
foundResources := 0
for _, res := range psiResources { for _, res := range psiResources {
c.logger.Debug("collecting statistics for resource", "resource", res) c.logger.Debug("collecting statistics for resource", "resource", res)
vals, err := c.fs.PSIStatsForResource(res) vals, err := c.fs.PSIStatsForResource(res)
if err != nil { if err != nil {
if errors.Is(err, os.ErrNotExist) { if errors.Is(err, os.ErrNotExist) && res != psiResourceIRQ {
c.logger.Debug("pressure information is unavailable, you need a Linux kernel >= 4.20 and/or CONFIG_PSI enabled for your kernel") c.logger.Debug("pressure information is unavailable, you need a Linux kernel >= 4.20 and/or CONFIG_PSI enabled for your kernel", "resource", res)
return ErrNoData continue
}
if errors.Is(err, os.ErrNotExist) && res == psiResourceIRQ {
c.logger.Debug("pressure information is unavailable, you need a Linux kernel >= 6.1 and/or CONFIG_PSI enabled for your kernel", "resource", res)
continue
} }
if errors.Is(err, syscall.ENOTSUP) { if errors.Is(err, syscall.ENOTSUP) {
c.logger.Debug("pressure information is disabled, add psi=1 kernel command line to enable it") c.logger.Debug("pressure information is disabled, add psi=1 kernel command line to enable it")
@ -130,7 +142,14 @@ func (c *pressureStatsCollector) Update(ch chan<- prometheus.Metric) error {
ch <- prometheus.MustNewConstMetric(c.irqFull, prometheus.CounterValue, float64(vals.Full.Total)/1000.0/1000.0) ch <- prometheus.MustNewConstMetric(c.irqFull, prometheus.CounterValue, float64(vals.Full.Total)/1000.0/1000.0)
default: default:
c.logger.Debug("did not account for resource", "resource", res) c.logger.Debug("did not account for resource", "resource", res)
continue
} }
foundResources++
}
if foundResources == 0 {
c.logger.Debug("pressure information is unavailable, you need a Linux kernel >= 4.20 and/or CONFIG_PSI enabled for your kernel")
return ErrNoData
} }
return nil return nil