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mirror of https://github.com/rclone/rclone synced 2024-12-23 14:23:44 +01:00

rc: add methods to turn on blocking and mutex profiling

This commit is contained in:
Nick Craig-Wood 2019-10-26 16:27:20 +01:00
parent a40cc1167d
commit 199ac61bde
2 changed files with 123 additions and 4 deletions

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@ -573,6 +573,44 @@ This shows the current version of go and the go runtime
- arch - cpu architecture in use according to Go
- goVersion - version of Go runtime in use
### debug/set-block-profile-rate: Set runtime.SetBlockProfileRate for blocking profiling. {#debug/set-block-profile-rate}
SetBlockProfileRate controls the fraction of goroutine blocking events
that are reported in the blocking profile. The profiler aims to sample
an average of one blocking event per rate nanoseconds spent blocked.
To include every blocking event in the profile, pass rate = 1. To turn
off profiling entirely, pass rate <= 0.
After calling this you can use this to see the blocking profile:
go tool pprof http://localhost:5572/debug/pprof/block
Parameters
- rate - int
### debug/set-mutex-profile-fraction: Set runtime.SetMutexProfileFraction for mutex profiling. {#debug/set-mutex-profile-fraction}
SetMutexProfileFraction controls the fraction of mutex contention
events that are reported in the mutex profile. On average 1/rate
events are reported. The previous rate is returned.
To turn off profiling entirely, pass rate 0. To just read the current
rate, pass rate < 0. (For n>1 the details of sampling may change.)
Once this is set you can look use this to profile the mutex contention:
go tool pprof http://localhost:5572/debug/pprof/mutex
Parameters
- rate - int
Results
- previousRate - int
### job/list: Lists the IDs of the running jobs {#job/list}
Parameters - None
@ -1197,13 +1235,20 @@ You can see a summary of profiles available at http://localhost:5572/debug/pprof
Here is how to use some of them:
* Memory: `go tool pprof http://localhost:5572/debug/pprof/heap`
* Go routines: `curl http://localhost:5572/debug/pprof/goroutine?debug=1`
* 30-second CPU profile: `go tool pprof http://localhost:5572/debug/pprof/profile`
* 5-second execution trace: `wget http://localhost:5572/debug/pprof/trace?seconds=5`
- Memory: `go tool pprof http://localhost:5572/debug/pprof/heap`
- Go routines: `curl http://localhost:5572/debug/pprof/goroutine?debug=1`
- 30-second CPU profile: `go tool pprof http://localhost:5572/debug/pprof/profile`
- 5-second execution trace: `wget http://localhost:5572/debug/pprof/trace?seconds=5`
- Goroutine blocking profile
- Enable first with: `rclone rc debug/set-block-profile-rate rate=1` ([docs](#debug/set-block-profile-rate))
- `go tool pprof http://localhost:5572/debug/pprof/block`
- Contended mutexes:
- Enable first with: `rclone rc debug/set-mutex-profile-fraction rate=1` ([docs](#debug/set-mutex-profile-fraction))
- `go tool pprof http://localhost:5572/debug/pprof/mutex`
See the [net/http/pprof docs](https://golang.org/pkg/net/http/pprof/)
for more info on how to use the profiling and for a general overview
see [the Go team's blog post on profiling go programs](https://blog.golang.org/profiling-go-programs).
The profiling hook is [zero overhead unless it is used](https://stackoverflow.com/q/26545159/164234).

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@ -261,3 +261,77 @@ func rcQuit(ctx context.Context, in Params) (out Params, err error) {
return nil, nil
}
func init() {
Add(Call{
Path: "debug/set-mutex-profile-fraction",
Fn: rcSetMutexProfileFraction,
Title: "Set runtime.SetMutexProfileFraction for mutex profiling.",
Help: `
SetMutexProfileFraction controls the fraction of mutex contention
events that are reported in the mutex profile. On average 1/rate
events are reported. The previous rate is returned.
To turn off profiling entirely, pass rate 0. To just read the current
rate, pass rate < 0. (For n>1 the details of sampling may change.)
Once this is set you can look use this to profile the mutex contention:
go tool pprof http://localhost:5572/debug/pprof/mutex
Parameters
- rate - int
Results
- previousRate - int
`,
})
}
// Terminates app
func rcSetMutexProfileFraction(ctx context.Context, in Params) (out Params, err error) {
rate, err := in.GetInt64("rate")
if err != nil {
return nil, err
}
previousRate := runtime.SetMutexProfileFraction(int(rate))
out = make(Params)
out["previousRate"] = previousRate
return out, nil
}
func init() {
Add(Call{
Path: "debug/set-block-profile-rate",
Fn: rcSetBlockProfileRate,
Title: "Set runtime.SetBlockProfileRate for blocking profiling.",
Help: `
SetBlockProfileRate controls the fraction of goroutine blocking events
that are reported in the blocking profile. The profiler aims to sample
an average of one blocking event per rate nanoseconds spent blocked.
To include every blocking event in the profile, pass rate = 1. To turn
off profiling entirely, pass rate <= 0.
After calling this you can use this to see the blocking profile:
go tool pprof http://localhost:5572/debug/pprof/block
Parameters
- rate - int
`,
})
}
// Terminates app
func rcSetBlockProfileRate(ctx context.Context, in Params) (out Params, err error) {
rate, err := in.GetInt64("rate")
if err != nil {
return nil, err
}
runtime.SetBlockProfileRate(int(rate))
return nil, nil
}