ceph-csi/e2e/vendor/github.com/prometheus/procfs/proc_psi.go
Niels de Vos f87d06ed85 build: move e2e dependencies into e2e/go.mod
Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>
2025-03-04 17:43:49 +01:00

103 lines
3.3 KiB
Go

// Copyright 2019 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package procfs
// The PSI / pressure interface is described at
// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/accounting/psi.txt
// Each resource (cpu, io, memory, ...) is exposed as a single file.
// Each file may contain up to two lines, one for "some" pressure and one for "full" pressure.
// Each line contains several averages (over n seconds) and a total in µs.
//
// Example io pressure file:
// > some avg10=0.06 avg60=0.21 avg300=0.99 total=8537362
// > full avg10=0.00 avg60=0.13 avg300=0.96 total=8183134
import (
"bufio"
"bytes"
"fmt"
"io"
"strings"
"github.com/prometheus/procfs/internal/util"
)
const lineFormat = "avg10=%f avg60=%f avg300=%f total=%d"
// PSILine is a single line of values as returned by `/proc/pressure/*`.
//
// The Avg entries are averages over n seconds, as a percentage.
// The Total line is in microseconds.
type PSILine struct {
Avg10 float64
Avg60 float64
Avg300 float64
Total uint64
}
// PSIStats represent pressure stall information from /proc/pressure/*
//
// "Some" indicates the share of time in which at least some tasks are stalled.
// "Full" indicates the share of time in which all non-idle tasks are stalled simultaneously.
type PSIStats struct {
Some *PSILine
Full *PSILine
}
// PSIStatsForResource reads pressure stall information for the specified
// resource from /proc/pressure/<resource>. At time of writing this can be
// either "cpu", "memory" or "io".
func (fs FS) PSIStatsForResource(resource string) (PSIStats, error) {
data, err := util.ReadFileNoStat(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
if err != nil {
return PSIStats{}, fmt.Errorf("%w: psi_stats: unavailable for %q: %w", ErrFileRead, resource, err)
}
return parsePSIStats(bytes.NewReader(data))
}
// parsePSIStats parses the specified file for pressure stall information.
func parsePSIStats(r io.Reader) (PSIStats, error) {
psiStats := PSIStats{}
scanner := bufio.NewScanner(r)
for scanner.Scan() {
l := scanner.Text()
prefix := strings.Split(l, " ")[0]
switch prefix {
case "some":
psi := PSILine{}
_, err := fmt.Sscanf(l, fmt.Sprintf("some %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
if err != nil {
return PSIStats{}, err
}
psiStats.Some = &psi
case "full":
psi := PSILine{}
_, err := fmt.Sscanf(l, fmt.Sprintf("full %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
if err != nil {
return PSIStats{}, err
}
psiStats.Full = &psi
default:
// If we encounter a line with an unknown prefix, ignore it and move on
// Should new measurement types be added in the future we'll simply ignore them instead
// of erroring on retrieval
continue
}
}
return psiStats, nil
}