forked from mirrors/gotosocial
acc333c40b
When GTS is running in a container runtime which has configured CPU or memory limits or under an init system that uses cgroups to impose CPU and memory limits the values the Go runtime sees for GOMAXPROCS and GOMEMLIMIT are still based on the host resources, not the cgroup. At least for the throttling middlewares which use GOMAXPROCS to configure their queue size, this can result in GTS running with values too big compared to the resources that will actuall be available to it. This introduces 2 dependencies which can pick up resource contraints from the current cgroup and tune the Go runtime accordingly. This should result in the different queues being appropriately sized and in general more predictable performance. These dependencies are a no-op on non-Linux systems or if running in a cgroup that doesn't set a limit on CPU or memory. The automatic tuning of GOMEMLIMIT can be disabled by either explicitly setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The automatic tuning of GOMAXPROCS can similarly be counteracted by setting GOMAXPROCS yourself.
130 lines
4 KiB
Go
130 lines
4 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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// Package maxprocs lets Go programs easily configure runtime.GOMAXPROCS to
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// match the configured Linux CPU quota. Unlike the top-level automaxprocs
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// package, it lets the caller configure logging and handle errors.
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package maxprocs // import "go.uber.org/automaxprocs/maxprocs"
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import (
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"os"
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"runtime"
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iruntime "go.uber.org/automaxprocs/internal/runtime"
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)
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const _maxProcsKey = "GOMAXPROCS"
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func currentMaxProcs() int {
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return runtime.GOMAXPROCS(0)
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}
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type config struct {
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printf func(string, ...interface{})
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procs func(int) (int, iruntime.CPUQuotaStatus, error)
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minGOMAXPROCS int
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}
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func (c *config) log(fmt string, args ...interface{}) {
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if c.printf != nil {
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c.printf(fmt, args...)
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}
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}
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// An Option alters the behavior of Set.
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type Option interface {
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apply(*config)
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}
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// Logger uses the supplied printf implementation for log output. By default,
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// Set doesn't log anything.
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func Logger(printf func(string, ...interface{})) Option {
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return optionFunc(func(cfg *config) {
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cfg.printf = printf
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})
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}
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// Min sets the minimum GOMAXPROCS value that will be used.
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// Any value below 1 is ignored.
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func Min(n int) Option {
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return optionFunc(func(cfg *config) {
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if n >= 1 {
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cfg.minGOMAXPROCS = n
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}
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})
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}
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type optionFunc func(*config)
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func (of optionFunc) apply(cfg *config) { of(cfg) }
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// Set GOMAXPROCS to match the Linux container CPU quota (if any), returning
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// any error encountered and an undo function.
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//
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// Set is a no-op on non-Linux systems and in Linux environments without a
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// configured CPU quota.
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func Set(opts ...Option) (func(), error) {
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cfg := &config{
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procs: iruntime.CPUQuotaToGOMAXPROCS,
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minGOMAXPROCS: 1,
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}
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for _, o := range opts {
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o.apply(cfg)
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}
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undoNoop := func() {
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cfg.log("maxprocs: No GOMAXPROCS change to reset")
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}
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// Honor the GOMAXPROCS environment variable if present. Otherwise, amend
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// `runtime.GOMAXPROCS()` with the current process' CPU quota if the OS is
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// Linux, and guarantee a minimum value of 1. The minimum guaranteed value
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// can be overridden using `maxprocs.Min()`.
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if max, exists := os.LookupEnv(_maxProcsKey); exists {
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cfg.log("maxprocs: Honoring GOMAXPROCS=%q as set in environment", max)
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return undoNoop, nil
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}
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maxProcs, status, err := cfg.procs(cfg.minGOMAXPROCS)
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if err != nil {
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return undoNoop, err
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}
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if status == iruntime.CPUQuotaUndefined {
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cfg.log("maxprocs: Leaving GOMAXPROCS=%v: CPU quota undefined", currentMaxProcs())
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return undoNoop, nil
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}
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prev := currentMaxProcs()
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undo := func() {
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cfg.log("maxprocs: Resetting GOMAXPROCS to %v", prev)
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runtime.GOMAXPROCS(prev)
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}
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switch status {
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case iruntime.CPUQuotaMinUsed:
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cfg.log("maxprocs: Updating GOMAXPROCS=%v: using minimum allowed GOMAXPROCS", maxProcs)
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case iruntime.CPUQuotaUsed:
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cfg.log("maxprocs: Updating GOMAXPROCS=%v: determined from CPU quota", maxProcs)
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}
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runtime.GOMAXPROCS(maxProcs)
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return undo, nil
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}
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