You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
101 lines
3.3 KiB
101 lines
3.3 KiB
// 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 (
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
"os"
|
|
"strings"
|
|
)
|
|
|
|
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) {
|
|
file, err := os.Open(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
|
|
if err != nil {
|
|
return PSIStats{}, fmt.Errorf("psi_stats: unavailable for %s", resource)
|
|
}
|
|
|
|
defer file.Close()
|
|
return parsePSIStats(resource, file)
|
|
}
|
|
|
|
// parsePSIStats parses the specified file for pressure stall information
|
|
func parsePSIStats(resource string, file io.Reader) (PSIStats, error) {
|
|
psiStats := PSIStats{}
|
|
stats, err := ioutil.ReadAll(file)
|
|
if err != nil {
|
|
return psiStats, fmt.Errorf("psi_stats: unable to read data for %s", resource)
|
|
}
|
|
|
|
for _, l := range strings.Split(string(stats), "\n") {
|
|
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
|
|
}
|
|
|