Go 1.24: Higher Mutex Wait Durations.

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Introduction

In this article, we will explore the issue of higher mutex wait durations in Go 1.24. We will discuss the problem, its symptoms, and possible causes. We will also examine the changes introduced in Go 1.24 that may be related to this issue.

Go Version

The Go version used in this case is 1.24.0 and 1.24.1. The output of go env is provided below:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='on'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHEPROG=''
GODEBUG=''
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build322822516=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOOS='linux'
GOROOT='/usr/lib/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.0'
GOWORK=''
PKG_CONFIG='pkg-config'

What Did You Do?

We upgraded a gRPC serving application's Go version from 1.23.3 to 1.24.0 and 1.24.1. The application is primarily IO-bound.

What Did You See Happen?

After the upgrade, we observed a significant increase in mutex wait durations by a factor of 2. The issue appears to be related to an unlock in context.(*cancelCtx).propagateCancel.

Prometheus Metrics

The Prometheus metrics go_sync_mutex_wait_total_seconds_total showed a significant increase in mutex wait durations after the upgrade.

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Pprof Profiles

The Pprof profiles also showed a significant increase in mutex wait durations in Go 1.24 compared to Go 1.23.

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What Did You Expect to See?

We expected to see improved CPU performance due to the changes introduced in Go 1.24, including a new runtime-internal mutex implementation. However, we observed a significant increase in mutex wait durations, which is counterintuitive.

Possible Causes

The possible causes of this issue are:

  1. Mutex Implementation Changes: The new runtime-internal mutex implementation in Go 1.24 may be causing the increase in mutex wait durations.
  2. Context Cancelation: The unlock in context.(*cancelCtx).propagateCancel may be causing the issue.
  3. Other Go 1.24 Changes: Other changes introduced in Go 1.24 may be contributing to the issue.

Conclusion

In conclusion, we observed a significant increase in mutex wait durations in Go 1.24 compared to Go 1.23. The issue appears to be related to an unlock in context.(*cancelCtx).propagateCancel. We also discussed possible causes of this issue, including mutex implementation changes and other Go 1.24 changes.

Recommendations

Based on our findings, we recommend:

  1. Investigate Mutex Implementation Changes: Investigate the new runtime-internal mutex implementation in Go 1.24 and its impact on mutex wait durations.
  2. Review Context Cancelation: Review the unlock in context.(*cancelCtx).propagateCancel and its potential impact on mutex wait durations.
  3. Test Other Go 1.24 Changes: Test other changes introduced in Go 1.24 to determine their impact on mutex wait durations.

Introduction

In our previous article, we explored the issue of higher mutex wait durations in Go 1.24. We discussed the problem, its symptoms, and possible causes. In this article, we will answer some frequently asked questions related to this issue.

Q: What is the impact of higher mutex wait durations on my application?

A: Higher mutex wait durations can lead to performance issues in your application. Mutexes are used to synchronize access to shared resources, and increased wait times can cause delays in your application's execution. This can result in slower response times, increased latency, and potentially even crashes.

Q: How can I measure mutex wait durations in my application?

A: You can use various tools to measure mutex wait durations in your application. Some popular options include:

  • Prometheus: You can use Prometheus to collect metrics on mutex wait durations. You can then use Grafana to visualize these metrics and identify potential issues.
  • Pprof: You can use Pprof to profile your application and identify performance bottlenecks, including mutex wait durations.
  • Go's built-in profiling tools: Go provides several built-in profiling tools, including the go tool pprof command, which can help you identify performance issues in your application.

Q: What are some possible causes of higher mutex wait durations in Go 1.24?

A: Some possible causes of higher mutex wait durations in Go 1.24 include:

  • Mutex implementation changes: The new runtime-internal mutex implementation in Go 1.24 may be causing the increase in mutex wait durations.
  • Context cancelation: The unlock in context.(*cancelCtx).propagateCancel may be causing the issue.
  • Other Go 1.24 changes: Other changes introduced in Go 1.24 may be contributing to the issue.

Q: How can I troubleshoot higher mutex wait durations in my application?

A: To troubleshoot higher mutex wait durations in your application, you can follow these steps:

  1. Collect metrics: Use tools like Prometheus to collect metrics on mutex wait durations.
  2. Profile your application: Use tools like Pprof to profile your application and identify performance bottlenecks.
  3. Analyze your code: Review your code to identify potential issues related to mutex usage.
  4. Test with a debugger: Use a debugger to step through your code and identify potential issues related to mutex usage.

Q: What are some best practices for using mutexes in Go?

A: Some best practices for using mutexes in Go include:

  • Use mutexes sparingly: Mutexes can introduce performance bottlenecks, so use them sparingly.
  • Use a mutex lock duration: Use a mutex lock duration to ensure that mutexes are released promptly.
  • Avoid deep nesting: Avoid deep nesting of mutex locks to prevent deadlocks.
  • Use a mutex pool: Use a mutex pool to reduce the overhead of creating and destroying mutexes.

Q: How can I upgrade to Go 1.24 while minimizing the risk of higher mutex wait durations?

A: To upgrade to Go 1.24 while minimizing the risk of higher mutex wait durations, you can follow these steps:

  1. Test your application: Test your application thoroughly before upgrading to Go 1.24.
  2. Monitor performance: Monitor your application's performance after upgrading to Go 1.24.
  3. Collect metrics: Collect metrics on mutex wait durations to identify potential issues.
  4. Profile your application: Profile your application to identify performance bottlenecks.

By following these best practices and troubleshooting steps, you can minimize the risk of higher mutex wait durations when upgrading to Go 1.24.