lib/cgroup: attempt to obtain available CPU cores via /sys/devices/system/cpu/online

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
This commit is contained in:
Aliaksandr Valialkin 2020-09-22 23:26:44 +03:00
parent 4ebd2fa560
commit 89d652b583
2 changed files with 75 additions and 0 deletions

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@ -1,8 +1,11 @@
package cgroup package cgroup
import ( import (
"io/ioutil"
"os" "os"
"runtime" "runtime"
"strconv"
"strings"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger" "github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
) )
@ -40,9 +43,57 @@ func getCPUQuota() float64 {
if err != nil { if err != nil {
return 0 return 0
} }
if quotaUS <= 0 {
// The quota isn't set. This may be the case in multilevel containers.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
return getOnlineCPUCount()
}
periodUS, err := readInt64("/sys/fs/cgroup/cpu/cpu.cfs_period_us", "cat /sys/fs/cgroup/cpu$(cat /proc/self/cgroup | grep cpu, | cut -d: -f3)/cpu.cfs_period_us") periodUS, err := readInt64("/sys/fs/cgroup/cpu/cpu.cfs_period_us", "cat /sys/fs/cgroup/cpu$(cat /proc/self/cgroup | grep cpu, | cut -d: -f3)/cpu.cfs_period_us")
if err != nil { if err != nil {
return 0 return 0
} }
return float64(quotaUS) / float64(periodUS) return float64(quotaUS) / float64(periodUS)
} }
func getOnlineCPUCount() float64 {
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
data, err := ioutil.ReadFile("/sys/devices/system/cpu/online")
if err != nil {
return -1
}
n := float64(countCPUs(string(data)))
if n <= 0 {
return -1
}
// Add a half of CPU core, since it looks like actual cores is usually bigger than online cores.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
return n + 0.5
}
func countCPUs(data string) int {
data = strings.TrimSpace(data)
n := 0
for _, s := range strings.Split(data, ",") {
n++
if !strings.Contains(s, "-") {
if _, err := strconv.Atoi(s); err != nil {
return -1
}
continue
}
bounds := strings.Split(s, "-")
if len(bounds) != 2 {
return -1
}
start, err := strconv.Atoi(bounds[0])
if err != nil {
return -1
}
end, err := strconv.Atoi(bounds[1])
if err != nil {
return -1
}
n += end - start
}
return n
}

24
lib/cgroup/cpu_test.go Normal file
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@ -0,0 +1,24 @@
package cgroup
import (
"testing"
)
func TestCountCPUs(t *testing.T) {
f := func(s string, nExpected int) {
t.Helper()
n := countCPUs(s)
if n != nExpected {
t.Fatalf("unexpected result from countCPUs(%q); got %d; want %d", s, n, nExpected)
}
}
f("", -1)
f("1", 1)
f("234", 1)
f("1,2", 2)
f("0-1", 2)
f("0-0", 1)
f("1-2,3,5-9,200-210", 19)
f("0-3", 4)
f("0-6", 7)
}