VictoriaMetrics/vendor/github.com/prometheus/procfs/proc_psi.go
Aliaksandr Valialkin 7f4fb34182 app/vmctl: move vmctl code from github.com/VictoriaMetrics/vmctl
It is better developing vmctl tool in VictoriaMetrics repository, so it could be released
together with the rest of vmutils tools such as vmalert, vmagent, vmbackup, vmrestore and vmauth.
2021-02-01 01:18:39 +02:00

100 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("psi_stats: unavailable for %s", resource)
}
return parsePSIStats(resource, bytes.NewReader(data))
}
// parsePSIStats parses the specified file for pressure stall information
func parsePSIStats(resource string, 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
}