Automatically set GOMAXPROCS to match Linux container CPU quota.

Overview

automaxprocs GoDoc Build Status Coverage Status

Automatically set GOMAXPROCS to match Linux container CPU quota.

Installation

go get -u go.uber.org/automaxprocs

Quick Start

import _ "go.uber.org/automaxprocs"

func main() {
  // Your application logic here.
}

Development Status: Stable

All APIs are finalized, and no breaking changes will be made in the 1.x series of releases. Users of semver-aware dependency management systems should pin automaxprocs to ^1.

Contributing

We encourage and support an active, healthy community of contributors — including you! Details are in the contribution guide and the code of conduct. The automaxprocs maintainers keep an eye on issues and pull requests, but you can also report any negative conduct to [email protected]. That email list is a private, safe space; even the automaxprocs maintainers don't have access, so don't hesitate to hold us to a high standard.


Released under the MIT License.

Comments
  • Support cgroup2

    Support cgroup2

    CGroup-V2 has a different architecture which is unified. Since it is not yet supported in go, it makes sense to currently have the support. This commit adds the functionality to set GOMAXPROCS in cgroup2 enabled systems.

    Also there were lint errors because of build annotation comments which are fixed in a separate commit.

    This PR resolves https://github.com/uber-go/automaxprocs/issues/21.

    opened by emadolsky 13
  • Add benchmarks to README?

    Add benchmarks to README?

    Hi! I was wondering if it would possible to include some benchmarks in the README? We run some open-source software with cpu quotas and being able to link to some benchmarks in the README might go a long way to convincing other people to incorporate automaxprocs into their projects as well.

    opened by jeromefroe 9
  • v1.5.0 I am still getting that the CPU Quota is not defined.

    v1.5.0 I am still getting that the CPU Quota is not defined.

    Originally posted by @ardan-bkennedy in https://github.com/uber-go/automaxprocs/issues/44#issuecomment-1089508688

    This change has not fixed the problem. I switched my code from "github.com/emadolsky/automaxprocs/maxprocs" to v1.5.0 and I am still getting that the CPU Quota is not defined.

    I noticed that in v1.5.0

    https://github.com/uber-go/automaxprocs/blob/v1.5.0/internal/runtime/cpu_quota_linux.go#L35

    func CPUQuotaToGOMAXPROCS(minValue int) (int, CPUQuotaStatus, error) {[Jason Lai, 5 years ago: • Import `automaxprocs/x/runtime`](https://sourcegraph.com/github.com/uber-go/automaxprocs/-/commit/572239b375b1ca6b76babeb8b0ee139dc35fd4d8)
    	cgroups, err := newQueryer()
    	if err != nil {
    		return -1, CPUQuotaUndefined, err
    	}
    
    	quota, defined, err := cgroups.CPUQuota()
    	if !defined || err != nil {
    		return -1, CPUQuotaUndefined, err
    	}
    
    	maxProcs := int(math.Floor(quota))
    	if minValue > 0 && maxProcs < minValue {
    		return minValue, CPUQuotaMinUsed, nil
    	}
    	return maxProcs, CPUQuotaUsed, nil
    }
    
    var (
    	_newCgroups2 = cg.NewCGroups2ForCurrentProcess
    	_newCgroups  = cg.NewCGroupsForCurrentProcess
    )
    
    func newQueryer() (queryer, error) {
    	cgroups, err := _newCgroups2()
    	if err == nil {
    		return cgroups, nil
    	}
    	if errors.Is(err, cg.ErrNotV2) {
    		return _newCgroups()
    	}
    	return nil, err
    }
    

    In the emadolsky repo, it's working. I don't know enough to tell you why.

    func CPUQuotaToGOMAXPROCS(minValue int) (int, CPUQuotaStatus, error) {
    	var quota float64
    	var defined bool
    	var err error
    
    	isV2, err := cg.IsCGroupV2()
    	if err != nil {
    		return -1, CPUQuotaUndefined, err
    	}
    
    	if isV2 {
    		quota, defined, err = cg.CPUQuotaV2()
    		if !defined || err != nil {
    			return -1, CPUQuotaUndefined, err
    		}
    	} else {
    		cgroups, err := cg.NewCGroupsForCurrentProcess()
    		if err != nil {
    			return -1, CPUQuotaUndefined, err
    		}
    
    		quota, defined, err = cgroups.CPUQuota()
    		if !defined || err != nil {
    			return -1, CPUQuotaUndefined, err
    		}
    	}
    
    	maxProcs := int(math.Floor(quota))
    	if minValue > 0 && maxProcs < minValue {
    		return minValue, CPUQuotaMinUsed, nil
    	}
    	return maxProcs, CPUQuotaUsed, nil
    }
    
    opened by dprotaso 8
  • maxprocs: CPU quota undefined

    maxprocs: CPU quota undefined

    This has not always been the case and I have tried to trace the code, but I don't know enough.

    The project in question is https://github.com/ardanlabs/service and I am using KIND.

    It seems to me /proc/self/cgroup is missing from the list of SuperOptions. Not sure why this is now happening.

    Any guidance to debug or understand this would be appreciated. I can walk someone to run the code.

    opened by ardan-bkennedy 7
  • Support child control cgroups in cgroupsv2

    Support child control cgroups in cgroupsv2

    The original v2 support code does not support child control groups. This commit fixes that.

    For how child control groups are organized see: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_monitoring_and_updating_the_kernel/using-cgroups-v2-to-control-distribution-of-cpu-time-for-applications_managing-monitoring-and-updating-the-kernel

    opened by maciej 5
  • Move lint tooling install to CI

    Move lint tooling install to CI

    Lint tools added to the main project's go.mod results in about an extra megabyte of vendored libs for all library consumers

    ❯ du -h vendor/honnef.co/go/tools
    4.0K    vendor/honnef.co/go/tools/arg
    8.0K    vendor/honnef.co/go/tools/cmd/staticcheck
    8.0K    vendor/honnef.co/go/tools/cmd
    12K     vendor/honnef.co/go/tools/config
    8.0K    vendor/honnef.co/go/tools/deprecated
    20K     vendor/honnef.co/go/tools/facts
    12K     vendor/honnef.co/go/tools/functions
    32K     vendor/honnef.co/go/tools/go/types/typeutil
    32K     vendor/honnef.co/go/tools/go/types
    32K     vendor/honnef.co/go/tools/go
    28K     vendor/honnef.co/go/tools/internal/cache
    4.0K    vendor/honnef.co/go/tools/internal/passes/buildssa
    4.0K    vendor/honnef.co/go/tools/internal/passes
    4.0K    vendor/honnef.co/go/tools/internal/renameio
    4.0K    vendor/honnef.co/go/tools/internal/sharedcheck
    40K     vendor/honnef.co/go/tools/internal
    12K     vendor/honnef.co/go/tools/lint/lintdsl
    4.0K    vendor/honnef.co/go/tools/lint/lintutil/format
    28K     vendor/honnef.co/go/tools/lint/lintutil
    88K     vendor/honnef.co/go/tools/lint
    8.0K    vendor/honnef.co/go/tools/loader
    12K     vendor/honnef.co/go/tools/printf
    72K     vendor/honnef.co/go/tools/simple
    328K    vendor/honnef.co/go/tools/ssa
    4.0K    vendor/honnef.co/go/tools/ssautil
    60K     vendor/honnef.co/go/tools/staticcheck/vrp
    216K    vendor/honnef.co/go/tools/staticcheck
    40K     vendor/honnef.co/go/tools/stylecheck
    72K     vendor/honnef.co/go/tools/unused
    12K     vendor/honnef.co/go/tools/version
    1004K   vendor/honnef.co/go/tools
    

    We can move to a more adhoc install process during CI to avoid this. This was tested by running inside a debian docker container, but will ensure CI still passes through Travis as well

    opened by ndisidore 5
  • Needs readme, with bonus screenshots

    Needs readme, with bonus screenshots

    People shouldn't land on our repos and be expected to write/run code to see what it does. Take a look at any of our other big OSS projects for a sense of what we're looking for.

    cc @prashantv not sure how this got past the internal review

    opened by ascandella 5
  • Use floor(quota) rather than ceil(quota)

    Use floor(quota) rather than ceil(quota)

    Apologies, this was an oversight on my part back when we wrote the x/runtime precursor that I helped to review. I'd since been working on the (it turns out false) assumption that this had been floor all along. Recent investigation into pervasive low-grade throttling tho led me to this discovery.

    In short:

    • as far as the Go scheduler is concerned, there's no such thing as a fractional CPU
    • so let's say you have your quota set to N + p for some integer N and some 0.0 < p < 1.0
    • the only safe assumption then is that you're using that p value as a hedge for something like "systems effects" or "c libraries"
      • in that latter case, what you really might want to be able give maxprocs some value K of reserved CPUs for some parasite like a C library or sidecar; but that's probably more of an option for our Fx wrapper?
    opened by jcorbin 3
  • is it not default behavior after version 1.5?

    is it not default behavior after version 1.5?

    hi, I am curious that isn't it auto set GOMAXPROCS to the cpu core number?just as this StackOverflow answer says, from version 1.5, it is a default behavior

    opened by huahuayu 2
  • tools: Move to submodule

    tools: Move to submodule

    Move lint dependencies to a tools submodule so that these are not introduced as dependencies of the package.

    In other projects, we experimented with renaming tools.go to tools_test.go but that wasn't enough either. The tools submodule appears to be the safest approach.

    Supersedes #32 Refs uber-go/atomic#78

    opened by abhinav 2
  • Fix cgroup sub system parsing with names containing colons

    Fix cgroup sub system parsing with names containing colons

    cgroup sub system names can contain colons which is also used as separator symbol, e.g.:

    12:cpu,cpuacct:/system.slice/containerd.service/kubepods-besteffort-podb41662f7_b03a_4c65_8ef9_6e4e55c3cf27.slice:cri-containerd:1753b7cbbf62734d812936961224d5bc0cf8f45214e0d5cdd1a781a053e7c48f
    
    opened by mtneug 2
  • feature: set GOMAXPROCS env var during Set

    feature: set GOMAXPROCS env var during Set

    Currently, when do import _ "go.uber.org/automaxprocs", the GOMAXPROCS is set automatically for users. But it doesn't set up the GOMAXPROCS environment variable which means if the programs exec some children processes to do some work, the env var needs to be set up manually.

    For me, I think there are no side effects to setup the GOMAXPROCS environment variable also when we set up it in the program. So I raised this PR.

    Regrads.

    opened by xieyuschen 1
  • What happens if cpu quota on k8s side is less than 1 core?

    What happens if cpu quota on k8s side is less than 1 core?

    Am i right that if you have a service with a cpu limit less than 1000m (eg 1 core) the go process would still think it has one core available and tries to utilize more than its limit to get throttled eventually. So my understanding here is that if you do use limits less than one core is a very unideal situation for the go-scheduler to work efficently:

    a.) 4 replicas with 500m cpu limit b.) 2 replicas with 1000m cpu limit

    In total both cases use the same amount of total cores (2) but case b.) would be more efficient as the go scheduler knows how much it can utilize?

    Sorry that i created a bug ticket for my simple question. But i think if my assumptions are correct, it would be good to make this clear in the README.

    Thanks for the awesome library :+1:

    opened by timo-klarshift 6
  • Fix mountpoint multiple match

    Fix mountpoint multiple match

    When use make test base on this case 8 5 0:7 /docker /sys/fs/cgroup/memory rw,nosuid,nodev,noexec,relatime shared:8 - cgroup cgroup rw,memory 9 5 0:8 /docker/memory.vmstat /sys/fs/cgroup/vmstat rw,nosuid,nodev,noexec,relatime shared:8 - cgroup cgroup rw,memory been failed.

    Because it's match multiple target,cannot uniquely match

    opened by coco-roll 4
  • no cgroup mountinfo in /proc/self/mountinfo if shareProcessNamespace=true

    no cgroup mountinfo in /proc/self/mountinfo if shareProcessNamespace=true

    when shareProcessNamespace=true, business container's pid is not equals to 1. There is no cgroup mountinfo in /proc/self/mountinfo, but it is in /proc/1/mountinfo.

    opened by stonewesley 0
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